[CLAUDE] Domain+App+Api: Module Ngan sach (Budget) - 4 bang + workflow simple

User request: 'Them cho tao 4 bang luu ve ngan sach: Header / Chi tiet
/ Quy trinh duyet / Lich su thay doi'.

Domain (5 file + 1 enum):
 - Budget (header) — Aggregate root, AuditableEntity. Field: MaNganSach,
   TenNganSach, Description, NamNganSach, ProjectId FK, DepartmentId?,
   DrafterUserId, Phase (BudgetPhase 5-state), TongNganSach (sum auto
   tu Details), SlaDeadline, SlaWarningSent.
 - BudgetDetail — flat row pattern (GroupCode/GroupName + Item +
   KhoiLuong/DonGia/ThanhTien). 18,4 precision KhoiLuong, 18,2 money.
 - BudgetApproval — workflow history (FromPhase/ToPhase/Decision/Comment)
 - BudgetChangelog — audit log unified (EntityType: Header/Detail/Workflow)
 - BudgetPhase enum 5 state: DangSoanThao(1) → ChoCCM(2) → ChoCEO(3) →
   DaDuyet(4) | TuChoi(99)
 - BudgetPolicy hardcoded (no versioned WF, simple default per user
   confirm 'tam thoi don gian'): Drafter/DeptManager → CCM → CEO/
   AuthorizedSigner. Reject path back to DangSoanThao.

Migration 14 AddBudgets:
 - 4 bang moi: Budgets + BudgetDetails + BudgetApprovals + BudgetChangelogs
 - Index: Phase+IsDeleted, ProjectId, NamNganSach, SlaDeadline,
   MaNganSach unique filtered. Cascade delete child.
 - +2 cot FK ngoai bang (per user 'lien ket ca 3'):
   * Contracts.BudgetId Guid? + index
   * PurchaseEvaluations.BudgetId Guid? + index
   Cho phep doi chieu chi phi HD/PE vs ngan sach goi thau.

Application CQRS (BudgetFeatures.cs ~340 line):
 - CreateBudget + UpdateBudgetDraft + TransitionBudget + ListBudgets
   (filter Phase/Project/Year + search + paging) + GetBudget bundle
   (Header + Details + Approvals + Workflow summary)
 - DeleteBudget (only DangSoanThao/TuChoi)
 - AddBudgetDetail + UpdateBudgetDetail + DeleteBudgetDetail (auto
   recompute TongNganSach = sum Details.ThanhTien)
 - ListBudgetChangelogs

Api: BudgetsController 11 endpoint REST /api/budgets:
 - GET /  /{id}  /{id}/changelogs
 - POST /  /{id}/transitions  /{id}/details
 - PUT /{id}  /{id}/details/{detailId}
 - DELETE /{id}  /{id}/details/{detailId}

DbContext + IApplicationDbContext: 4 DbSet new (Budgets/Details/
Approvals/Changelogs).

MenuKeys + DbInitializer: 4 menu key (Budgets root + Bg_List/Create/
Pending leaves) seed dau order=27 'Ngan sach' icon Wallet. Auto-grant
admin permission via SeedAdminPermissionsAsync (MenuKeys.All).

MaNganSach format don gian 'NS-YYYYMM-NNNN' Random.Shared (chua atomic
sequence - user said 'tam thoi chua co').

Workflow chua versioned, hardcode BudgetPolicy.Default. Tuong lai admin
config qua UI: them BudgetWorkflowDefinition tables tuong tu PE.

src/Backend/SolutionErp.Api/Controllers/BudgetsController.cs

@@ -0,0 +1,94 @@
+using MediatR;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using SolutionErp.Application.Budgets;
+using SolutionErp.Application.Budgets.Dtos;
+using SolutionErp.Application.Common.Models;
+using SolutionErp.Domain.Budgets;
+using SolutionErp.Domain.Contracts;
+
+namespace SolutionErp.Api.Controllers;
+
+[ApiController]
+[Route("api/budgets")]
+[Authorize]
+public class BudgetsController(IMediator mediator) : ControllerBase
+{
+    [HttpGet]
+    public async Task<ActionResult<PagedResult<BudgetListItemDto>>> List(
+        [FromQuery] int page = 1, [FromQuery] int pageSize = 20,
+        [FromQuery] string? search = null, [FromQuery] bool sortDesc = true,
+        [FromQuery] BudgetPhase? phase = null,
+        [FromQuery] Guid? projectId = null,
+        [FromQuery] int? namNganSach = null,
+        CancellationToken ct = default)
+        => Ok(await mediator.Send(new ListBudgetsQuery(phase, projectId, namNganSach)
+        { Page = page, PageSize = pageSize, Search = search, SortDesc = sortDesc }, ct));
+
+    [HttpGet("{id:guid}")]
+    public async Task<ActionResult<BudgetDetailBundleDto>> Get(Guid id, CancellationToken ct)
+        => Ok(await mediator.Send(new GetBudgetQuery(id), ct));
+
+    [HttpPost]
+    public async Task<ActionResult<object>> Create([FromBody] CreateBudgetCommand cmd, CancellationToken ct)
+    {
+        var id = await mediator.Send(cmd, ct);
+        return CreatedAtAction(nameof(Get), new { id }, new { id });
+    }
+
+    [HttpPut("{id:guid}")]
+    public async Task<IActionResult> Update(Guid id, [FromBody] UpdateBudgetDraftCommand cmd, CancellationToken ct)
+    {
+        if (id != cmd.Id) return BadRequest(new { detail = "ID không khớp" });
+        await mediator.Send(cmd, ct);
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/transitions")]
+    public async Task<IActionResult> Transition(Guid id, [FromBody] TransitionBudgetBody body, CancellationToken ct)
+    {
+        await mediator.Send(new TransitionBudgetCommand(id, body.TargetPhase, body.Decision, body.Comment), ct);
+        return NoContent();
+    }
+
+    [HttpDelete("{id:guid}")]
+    public async Task<IActionResult> Delete(Guid id, CancellationToken ct)
+    {
+        await mediator.Send(new DeleteBudgetCommand(id), ct);
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/details")]
+    public async Task<ActionResult<object>> AddDetail(Guid id, [FromBody] BudgetDetailBody body, CancellationToken ct)
+    {
+        var newId = await mediator.Send(new AddBudgetDetailCommand(
+            id, body.GroupCode, body.GroupName, body.ItemCode, body.NoiDung, body.DonViTinh,
+            body.KhoiLuong, body.DonGia, body.ThanhTien, body.GhiChu), ct);
+        return Ok(new { id = newId });
+    }
+
+    [HttpPut("{id:guid}/details/{detailId:guid}")]
+    public async Task<IActionResult> UpdateDetail(Guid id, Guid detailId, [FromBody] BudgetDetailBody body, CancellationToken ct)
+    {
+        await mediator.Send(new UpdateBudgetDetailCommand(
+            id, detailId, body.GroupCode, body.GroupName, body.ItemCode, body.NoiDung, body.DonViTinh,
+            body.KhoiLuong, body.DonGia, body.ThanhTien, body.GhiChu), ct);
+        return NoContent();
+    }
+
+    [HttpDelete("{id:guid}/details/{detailId:guid}")]
+    public async Task<IActionResult> DeleteDetail(Guid id, Guid detailId, CancellationToken ct)
+    {
+        await mediator.Send(new DeleteBudgetDetailCommand(id, detailId), ct);
+        return NoContent();
+    }
+
+    [HttpGet("{id:guid}/changelogs")]
+    public async Task<List<BudgetChangelogDto>> GetChangelogs(Guid id, CancellationToken ct)
+        => await mediator.Send(new ListBudgetChangelogsQuery(id), ct);
+}
+
+public record TransitionBudgetBody(BudgetPhase TargetPhase, ApprovalDecision Decision, string? Comment);
+public record BudgetDetailBody(
+    string GroupCode, string GroupName, string? ItemCode, string NoiDung,
+    string? DonViTinh, decimal KhoiLuong, decimal DonGia, decimal ThanhTien, string? GhiChu);

src/Backend/SolutionErp.Application/Budgets/BudgetFeatures.cs

@@ -0,0 +1,388 @@
+using FluentValidation;
+using MediatR;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.EntityFrameworkCore;
+using SolutionErp.Application.Budgets.Dtos;
+using SolutionErp.Application.Common.Exceptions;
+using SolutionErp.Application.Common.Interfaces;
+using SolutionErp.Application.Common.Models;
+using SolutionErp.Domain.Budgets;
+using SolutionErp.Domain.Contracts;   // ApprovalDecision + ChangelogAction
+using SolutionErp.Domain.Identity;
+
+namespace SolutionErp.Application.Budgets;
+
+// Compact CQRS feature file cho module Ngân sách. Pattern simplified vs PE
+// (no versioned WF, hardcoded BudgetPolicy.Default). Workflow 5 phase:
+// DangSoanThao → ChoCCM → ChoCEO → DaDuyet/TuChoi.
+
+// ========== CREATE ==========
+
+public record CreateBudgetCommand(
+    string TenNganSach,
+    string? Description,
+    int NamNganSach,
+    Guid ProjectId,
+    Guid? DepartmentId) : IRequest<Guid>;
+
+public class CreateBudgetCommandValidator : AbstractValidator<CreateBudgetCommand>
+{
+    public CreateBudgetCommandValidator()
+    {
+        RuleFor(x => x.TenNganSach).NotEmpty().MaximumLength(500);
+        RuleFor(x => x.Description).MaximumLength(2000);
+        RuleFor(x => x.ProjectId).NotEmpty();
+        RuleFor(x => x.NamNganSach).InclusiveBetween(2020, 2100);
+    }
+}
+
+public class CreateBudgetCommandHandler(
+    IApplicationDbContext db,
+    ICurrentUser currentUser) : IRequestHandler<CreateBudgetCommand, Guid>
+{
+    public async Task<Guid> Handle(CreateBudgetCommand request, CancellationToken ct)
+    {
+        _ = await db.Projects.FirstOrDefaultAsync(p => p.Id == request.ProjectId, ct)
+            ?? throw new NotFoundException("Project", request.ProjectId);
+
+        var sla = BudgetPolicies.Default.PhaseSla.GetValueOrDefault(BudgetPhase.DangSoanThao);
+        var entity = new Budget
+        {
+            TenNganSach = request.TenNganSach,
+            Description = request.Description,
+            NamNganSach = request.NamNganSach,
+            ProjectId = request.ProjectId,
+            DepartmentId = request.DepartmentId,
+            DrafterUserId = currentUser.UserId,
+            Phase = BudgetPhase.DangSoanThao,
+            TongNganSach = 0,
+            SlaDeadline = sla is null ? null : DateTime.UtcNow.Add(sla.Value),
+            // Auto-gen MaNganSach đơn giản — atomic sequence sau (Phase 8)
+            MaNganSach = $"NS-{DateTime.UtcNow:yyyyMM}-{Random.Shared.Next(1000, 9999)}",
+        };
+        db.Budgets.Add(entity);
+
+        db.BudgetChangelogs.Add(new BudgetChangelog
+        {
+            BudgetId = entity.Id,
+            EntityType = BudgetEntityType.Header,
+            Action = ChangelogAction.Insert,
+            PhaseAtChange = entity.Phase,
+            UserId = currentUser.UserId,
+            Summary = $"Tạo ngân sách {entity.MaNganSach} — {entity.TenNganSach}",
+        });
+
+        await db.SaveChangesAsync(ct);
+        return entity.Id;
+    }
+}
+
+// ========== UPDATE draft ==========
+
+public record UpdateBudgetDraftCommand(
+    Guid Id,
+    string TenNganSach,
+    string? Description,
+    int NamNganSach) : IRequest;
+
+public class UpdateBudgetDraftCommandHandler(
+    IApplicationDbContext db,
+    ICurrentUser currentUser) : IRequestHandler<UpdateBudgetDraftCommand>
+{
+    public async Task Handle(UpdateBudgetDraftCommand request, CancellationToken ct)
+    {
+        var entity = await db.Budgets.FirstOrDefaultAsync(x => x.Id == request.Id, ct)
+            ?? throw new NotFoundException("Budget", request.Id);
+        if (entity.Phase != BudgetPhase.DangSoanThao)
+            throw new ConflictException("Chỉ sửa được ngân sách khi Đang soạn thảo.");
+
+        entity.TenNganSach = request.TenNganSach;
+        entity.Description = request.Description;
+        entity.NamNganSach = request.NamNganSach;
+
+        db.BudgetChangelogs.Add(new BudgetChangelog
+        {
+            BudgetId = entity.Id,
+            EntityType = BudgetEntityType.Header,
+            Action = ChangelogAction.Update,
+            PhaseAtChange = entity.Phase,
+            UserId = currentUser.UserId,
+            Summary = "Cập nhật ngân sách",
+        });
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+// ========== TRANSITION ==========
+
+public record TransitionBudgetCommand(
+    Guid Id, BudgetPhase TargetPhase, ApprovalDecision Decision, string? Comment) : IRequest;
+
+public class TransitionBudgetCommandHandler(
+    IApplicationDbContext db,
+    ICurrentUser currentUser,
+    UserManager<User> userManager) : IRequestHandler<TransitionBudgetCommand>
+{
+    public async Task Handle(TransitionBudgetCommand request, CancellationToken ct)
+    {
+        if (!currentUser.IsAuthenticated || currentUser.UserId is null)
+            throw new UnauthorizedException();
+
+        var entity = await db.Budgets.FirstOrDefaultAsync(x => x.Id == request.Id, ct)
+            ?? throw new NotFoundException("Budget", request.Id);
+
+        var policy = BudgetPolicies.Default;
+        var isAdmin = currentUser.Roles.Contains(AppRoles.Admin);
+
+        if (!isAdmin && !policy.IsTransitionAllowed(entity.Phase, request.TargetPhase, currentUser.Roles))
+            throw new ForbiddenException(
+                $"Role không đủ quyền chuyển {entity.Phase} → {request.TargetPhase}.");
+
+        var fromPhase = entity.Phase;
+        entity.SlaWarningSent = false;
+        entity.Phase = request.TargetPhase;
+        var sla = policy.PhaseSla.GetValueOrDefault(request.TargetPhase);
+        entity.SlaDeadline = sla is null ? null : DateTime.UtcNow.Add(sla.Value);
+
+        db.BudgetApprovals.Add(new BudgetApproval
+        {
+            BudgetId = entity.Id,
+            FromPhase = fromPhase,
+            ToPhase = request.TargetPhase,
+            ApproverUserId = currentUser.UserId,
+            Decision = request.Decision,
+            Comment = request.Comment,
+            ApprovedAt = DateTime.UtcNow,
+        });
+
+        string? actorName = null;
+        if (currentUser.UserId is Guid uid)
+        {
+            var u = await userManager.FindByIdAsync(uid.ToString());
+            actorName = u?.FullName ?? u?.Email;
+        }
+        db.BudgetChangelogs.Add(new BudgetChangelog
+        {
+            BudgetId = entity.Id,
+            EntityType = BudgetEntityType.Workflow,
+            Action = ChangelogAction.Transition,
+            PhaseAtChange = request.TargetPhase,
+            UserId = currentUser.UserId,
+            UserName = actorName ?? "Hệ thống",
+            Summary = $"Chuyển phase {fromPhase} → {request.TargetPhase}",
+            ContextNote = request.Comment,
+        });
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+// ========== LIST ==========
+
+public record ListBudgetsQuery(
+    BudgetPhase? Phase = null,
+    Guid? ProjectId = null,
+    int? NamNganSach = null) : PagedRequest, IRequest<PagedResult<BudgetListItemDto>>;
+
+public class ListBudgetsQueryHandler(
+    IApplicationDbContext db) : IRequestHandler<ListBudgetsQuery, PagedResult<BudgetListItemDto>>
+{
+    public async Task<PagedResult<BudgetListItemDto>> Handle(ListBudgetsQuery request, CancellationToken ct)
+    {
+        var q = from e in db.Budgets.AsNoTracking()
+                join p in db.Projects.AsNoTracking() on e.ProjectId equals p.Id
+                select new { e, p };
+
+        if (request.Phase is not null) q = q.Where(x => x.e.Phase == request.Phase);
+        if (request.ProjectId is not null) q = q.Where(x => x.e.ProjectId == request.ProjectId);
+        if (request.NamNganSach is not null) q = q.Where(x => x.e.NamNganSach == request.NamNganSach);
+        if (!string.IsNullOrWhiteSpace(request.Search))
+        {
+            var s = request.Search.Trim();
+            q = q.Where(x => (x.e.MaNganSach != null && x.e.MaNganSach.Contains(s))
+                || x.e.TenNganSach.Contains(s) || x.p.Name.Contains(s));
+        }
+        q = request.SortDesc ? q.OrderByDescending(x => x.e.CreatedAt) : q.OrderBy(x => x.e.CreatedAt);
+
+        var total = await q.CountAsync(ct);
+        var items = await q.Skip((request.Page - 1) * request.PageSize).Take(request.PageSize)
+            .Select(x => new BudgetListItemDto(
+                x.e.Id, x.e.MaNganSach, x.e.TenNganSach, x.e.NamNganSach, x.e.Phase,
+                x.e.ProjectId, x.p.Name, x.e.TongNganSach, x.e.SlaDeadline, x.e.CreatedAt))
+            .ToListAsync(ct);
+        return new PagedResult<BudgetListItemDto>(items, total, request.Page, request.PageSize);
+    }
+}
+
+// ========== GET detail bundle ==========
+
+public record GetBudgetQuery(Guid Id) : IRequest<BudgetDetailBundleDto>;
+
+public class GetBudgetQueryHandler(
+    IApplicationDbContext db,
+    UserManager<User> userManager) : IRequestHandler<GetBudgetQuery, BudgetDetailBundleDto>
+{
+    public async Task<BudgetDetailBundleDto> Handle(GetBudgetQuery request, CancellationToken ct)
+    {
+        var e = await db.Budgets.AsNoTracking()
+            .Include(x => x.Details)
+            .Include(x => x.Approvals)
+            .FirstOrDefaultAsync(x => x.Id == request.Id, ct)
+            ?? throw new NotFoundException("Budget", request.Id);
+
+        var project = await db.Projects.AsNoTracking().FirstOrDefaultAsync(p => p.Id == e.ProjectId, ct);
+        var department = e.DepartmentId is null ? null : await db.Departments.AsNoTracking()
+            .FirstOrDefaultAsync(d => d.Id == e.DepartmentId, ct);
+
+        var userIds = new HashSet<Guid>();
+        if (e.DrafterUserId is Guid did) userIds.Add(did);
+        foreach (var a in e.Approvals) if (a.ApproverUserId is Guid aid) userIds.Add(aid);
+        var users = await userManager.Users.AsNoTracking()
+            .Where(u => userIds.Contains(u.Id))
+            .ToDictionaryAsync(u => u.Id, u => u.FullName, ct);
+
+        var policy = BudgetPolicies.Default;
+
+        return new BudgetDetailBundleDto(
+            e.Id, e.MaNganSach, e.TenNganSach, e.Description, e.NamNganSach, e.Phase,
+            e.ProjectId, project?.Name ?? "",
+            e.DepartmentId, department?.Name,
+            e.DrafterUserId, e.DrafterUserId is Guid d && users.TryGetValue(d, out var dn) ? dn : null,
+            e.TongNganSach, e.SlaDeadline, e.CreatedAt, e.UpdatedAt,
+            e.Details.OrderBy(d => d.Order).Select(d => new BudgetDetailDto(
+                d.Id, d.GroupCode, d.GroupName, d.ItemCode, d.NoiDung, d.DonViTinh,
+                d.KhoiLuong, d.DonGia, d.ThanhTien, d.Order, d.GhiChu)).ToList(),
+            e.Approvals.OrderBy(a => a.ApprovedAt).Select(a => new BudgetApprovalDto(
+                a.Id, a.FromPhase, a.ToPhase, a.ApproverUserId,
+                a.ApproverUserId is Guid uid && users.TryGetValue(uid, out var an) ? an : null,
+                a.Decision, a.Comment, a.ApprovedAt)).ToList(),
+            new BudgetWorkflowSummaryDto(
+                policy.Name, policy.Description,
+                policy.ActivePhases.ToList(),
+                policy.NextPhasesFrom(e.Phase).ToList()));
+    }
+}
+
+// ========== DELETE ==========
+
+public record DeleteBudgetCommand(Guid Id) : IRequest;
+
+public class DeleteBudgetCommandHandler(
+    IApplicationDbContext db) : IRequestHandler<DeleteBudgetCommand>
+{
+    public async Task Handle(DeleteBudgetCommand request, CancellationToken ct)
+    {
+        var entity = await db.Budgets.FirstOrDefaultAsync(x => x.Id == request.Id, ct)
+            ?? throw new NotFoundException("Budget", request.Id);
+        if (entity.Phase != BudgetPhase.DangSoanThao && entity.Phase != BudgetPhase.TuChoi)
+            throw new ConflictException("Chỉ xóa được ngân sách phase Soạn thảo / Từ chối.");
+        db.Budgets.Remove(entity);
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+// ========== Detail CRUD ==========
+
+public record AddBudgetDetailCommand(
+    Guid BudgetId, string GroupCode, string GroupName, string? ItemCode, string NoiDung,
+    string? DonViTinh, decimal KhoiLuong, decimal DonGia, decimal ThanhTien, string? GhiChu) : IRequest<Guid>;
+
+public class AddBudgetDetailCommandHandler(
+    IApplicationDbContext db,
+    ICurrentUser currentUser) : IRequestHandler<AddBudgetDetailCommand, Guid>
+{
+    public async Task<Guid> Handle(AddBudgetDetailCommand request, CancellationToken ct)
+    {
+        var bg = await db.Budgets.FirstOrDefaultAsync(x => x.Id == request.BudgetId, ct)
+            ?? throw new NotFoundException("Budget", request.BudgetId);
+        var maxOrder = await db.BudgetDetails.Where(d => d.BudgetId == bg.Id)
+            .Select(d => (int?)d.Order).MaxAsync(ct);
+        var entity = new BudgetDetail
+        {
+            BudgetId = bg.Id,
+            GroupCode = request.GroupCode, GroupName = request.GroupName,
+            ItemCode = request.ItemCode, NoiDung = request.NoiDung, DonViTinh = request.DonViTinh,
+            KhoiLuong = request.KhoiLuong, DonGia = request.DonGia, ThanhTien = request.ThanhTien,
+            GhiChu = request.GhiChu, Order = (maxOrder ?? 0) + 1,
+        };
+        db.BudgetDetails.Add(entity);
+
+        // Recompute TongNganSach
+        bg.TongNganSach = await db.BudgetDetails.Where(d => d.BudgetId == bg.Id)
+            .SumAsync(d => d.ThanhTien, ct) + entity.ThanhTien;
+
+        db.BudgetChangelogs.Add(new BudgetChangelog
+        {
+            BudgetId = bg.Id, EntityType = BudgetEntityType.Detail, EntityId = entity.Id,
+            Action = ChangelogAction.Insert, PhaseAtChange = bg.Phase,
+            UserId = currentUser.UserId,
+            Summary = $"Thêm hạng mục {request.GroupCode} — {request.NoiDung}",
+        });
+        await db.SaveChangesAsync(ct);
+        return entity.Id;
+    }
+}
+
+public record UpdateBudgetDetailCommand(
+    Guid BudgetId, Guid DetailId, string GroupCode, string GroupName, string? ItemCode, string NoiDung,
+    string? DonViTinh, decimal KhoiLuong, decimal DonGia, decimal ThanhTien, string? GhiChu) : IRequest;
+
+public class UpdateBudgetDetailCommandHandler(
+    IApplicationDbContext db) : IRequestHandler<UpdateBudgetDetailCommand>
+{
+    public async Task Handle(UpdateBudgetDetailCommand request, CancellationToken ct)
+    {
+        var entity = await db.BudgetDetails
+            .FirstOrDefaultAsync(d => d.Id == request.DetailId && d.BudgetId == request.BudgetId, ct)
+            ?? throw new NotFoundException("BudgetDetail", request.DetailId);
+        entity.GroupCode = request.GroupCode; entity.GroupName = request.GroupName;
+        entity.ItemCode = request.ItemCode; entity.NoiDung = request.NoiDung; entity.DonViTinh = request.DonViTinh;
+        entity.KhoiLuong = request.KhoiLuong; entity.DonGia = request.DonGia; entity.ThanhTien = request.ThanhTien;
+        entity.GhiChu = request.GhiChu;
+
+        var bg = await db.Budgets.FirstOrDefaultAsync(b => b.Id == request.BudgetId, ct);
+        if (bg != null)
+            bg.TongNganSach = await db.BudgetDetails.Where(d => d.BudgetId == bg.Id)
+                .SumAsync(d => d.ThanhTien, ct);
+
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record DeleteBudgetDetailCommand(Guid BudgetId, Guid DetailId) : IRequest;
+
+public class DeleteBudgetDetailCommandHandler(
+    IApplicationDbContext db) : IRequestHandler<DeleteBudgetDetailCommand>
+{
+    public async Task Handle(DeleteBudgetDetailCommand request, CancellationToken ct)
+    {
+        var entity = await db.BudgetDetails
+            .FirstOrDefaultAsync(d => d.Id == request.DetailId && d.BudgetId == request.BudgetId, ct)
+            ?? throw new NotFoundException("BudgetDetail", request.DetailId);
+        db.BudgetDetails.Remove(entity);
+
+        var bg = await db.Budgets.FirstOrDefaultAsync(b => b.Id == request.BudgetId, ct);
+        if (bg != null)
+            bg.TongNganSach = await db.BudgetDetails.Where(d => d.BudgetId == bg.Id && d.Id != entity.Id)
+                .SumAsync(d => d.ThanhTien, ct);
+
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+// ========== CHANGELOG list ==========
+
+public record ListBudgetChangelogsQuery(Guid BudgetId, int Take = 200) : IRequest<List<BudgetChangelogDto>>;
+
+public class ListBudgetChangelogsQueryHandler(IApplicationDbContext db)
+    : IRequestHandler<ListBudgetChangelogsQuery, List<BudgetChangelogDto>>
+{
+    public async Task<List<BudgetChangelogDto>> Handle(ListBudgetChangelogsQuery request, CancellationToken ct) =>
+        await db.BudgetChangelogs.AsNoTracking()
+            .Where(c => c.BudgetId == request.BudgetId)
+            .OrderByDescending(c => c.CreatedAt)
+            .Take(request.Take)
+            .Select(c => new BudgetChangelogDto(
+                c.Id, c.EntityType, c.EntityId, c.Action, c.PhaseAtChange,
+                c.UserId, c.UserName, c.Summary, c.FieldChangesJson, c.ContextNote, c.CreatedAt))
+            .ToListAsync(ct);
+}

src/Backend/SolutionErp.Application/Budgets/Dtos/BudgetDtos.cs

@@ -0,0 +1,79 @@
+using SolutionErp.Domain.Budgets;
+using SolutionErp.Domain.Contracts;
+
+namespace SolutionErp.Application.Budgets.Dtos;
+
+public record BudgetListItemDto(
+    Guid Id,
+    string? MaNganSach,
+    string TenNganSach,
+    int NamNganSach,
+    BudgetPhase Phase,
+    Guid ProjectId,
+    string ProjectName,
+    decimal TongNganSach,
+    DateTime? SlaDeadline,
+    DateTime CreatedAt);
+
+public record BudgetDetailDto(
+    Guid Id,
+    string GroupCode,
+    string GroupName,
+    string? ItemCode,
+    string NoiDung,
+    string? DonViTinh,
+    decimal KhoiLuong,
+    decimal DonGia,
+    decimal ThanhTien,
+    int Order,
+    string? GhiChu);
+
+public record BudgetApprovalDto(
+    Guid Id,
+    BudgetPhase FromPhase,
+    BudgetPhase ToPhase,
+    Guid? ApproverUserId,
+    string? ApproverName,
+    ApprovalDecision Decision,
+    string? Comment,
+    DateTime ApprovedAt);
+
+public record BudgetChangelogDto(
+    Guid Id,
+    BudgetEntityType EntityType,
+    Guid? EntityId,
+    ChangelogAction Action,
+    BudgetPhase? PhaseAtChange,
+    Guid? UserId,
+    string? UserName,
+    string? Summary,
+    string? FieldChangesJson,
+    string? ContextNote,
+    DateTime CreatedAt);
+
+public record BudgetWorkflowSummaryDto(
+    string PolicyName,
+    string PolicyDescription,
+    List<BudgetPhase> ActivePhases,
+    List<BudgetPhase> NextPhases);
+
+public record BudgetDetailBundleDto(
+    Guid Id,
+    string? MaNganSach,
+    string TenNganSach,
+    string? Description,
+    int NamNganSach,
+    BudgetPhase Phase,
+    Guid ProjectId,
+    string ProjectName,
+    Guid? DepartmentId,
+    string? DepartmentName,
+    Guid? DrafterUserId,
+    string? DrafterName,
+    decimal TongNganSach,
+    DateTime? SlaDeadline,
+    DateTime CreatedAt,
+    DateTime? UpdatedAt,
+    List<BudgetDetailDto> Details,
+    List<BudgetApprovalDto> Approvals,
+    BudgetWorkflowSummaryDto Workflow);

src/Backend/SolutionErp.Application/Common/Interfaces/IApplicationDbContext.cs

@@ -1,4 +1,5 @@
 using Microsoft.EntityFrameworkCore;
+using SolutionErp.Domain.Budgets;
 using SolutionErp.Domain.Contracts;
 using SolutionErp.Domain.Contracts.Details;
 using SolutionErp.Domain.Forms;
@@ -58,5 +59,11 @@ public interface IApplicationDbContext
     DbSet<PurchaseEvaluationWorkflowStepApprover> PurchaseEvaluationWorkflowStepApprovers { get; }
     DbSet<PurchaseEvaluationCodeSequence> PurchaseEvaluationCodeSequences { get; }
 
+    // Module Ngân sách (Phase 7)
+    DbSet<Budget> Budgets { get; }
+    DbSet<BudgetDetail> BudgetDetails { get; }
+    DbSet<BudgetApproval> BudgetApprovals { get; }
+    DbSet<BudgetChangelog> BudgetChangelogs { get; }
+
     Task<int> SaveChangesAsync(CancellationToken cancellationToken = default);
 }

src/Backend/SolutionErp.Domain/Budgets/Budget.cs

@@ -0,0 +1,29 @@
+using SolutionErp.Domain.Common;
+
+namespace SolutionErp.Domain.Budgets;
+
+// Aggregate root quản lý ngân sách. Gắn với Project (required), reference
+// từ PurchaseEvaluation + Contract (cả 2 nullable FK Budget.Id).
+//
+// Workflow đơn giản 3-step: Drafter → CCM → CEO. Pattern hardcoded trong
+// BudgetPolicy (chưa versioned, tương lai có thể thêm BudgetWorkflowDefinition
+// nếu cần admin config).
+public class Budget : AuditableEntity
+{
+    public string? MaNganSach { get; set; }                  // Auto-gen NS-YYYYMM-XXXX
+    public string TenNganSach { get; set; } = string.Empty;
+    public string? Description { get; set; }
+    public int NamNganSach { get; set; }                     // Năm áp dụng (vd 2026)
+    public Guid ProjectId { get; set; }                      // FK Projects (required)
+    public Guid? DepartmentId { get; set; }
+    public Guid? DrafterUserId { get; set; }
+
+    public BudgetPhase Phase { get; set; } = BudgetPhase.DangSoanThao;
+    public decimal TongNganSach { get; set; }                // Tổng = sum BudgetDetails.ThanhTien (computed)
+    public DateTime? SlaDeadline { get; set; }
+    public bool SlaWarningSent { get; set; }
+
+    public List<BudgetDetail> Details { get; set; } = new();
+    public List<BudgetApproval> Approvals { get; set; } = new();
+    public List<BudgetChangelog> Changelogs { get; set; } = new();
+}

src/Backend/SolutionErp.Domain/Budgets/BudgetApproval.cs

@@ -0,0 +1,17 @@
+using SolutionErp.Domain.Common;
+using SolutionErp.Domain.Contracts;   // reuse ApprovalDecision
+
+namespace SolutionErp.Domain.Budgets;
+
+public class BudgetApproval : BaseEntity
+{
+    public Guid BudgetId { get; set; }
+    public BudgetPhase FromPhase { get; set; }
+    public BudgetPhase ToPhase { get; set; }
+    public Guid? ApproverUserId { get; set; }                // null = system SLA auto
+    public ApprovalDecision Decision { get; set; }
+    public string? Comment { get; set; }
+    public DateTime ApprovedAt { get; set; }
+
+    public Budget? Budget { get; set; }
+}

src/Backend/SolutionErp.Domain/Budgets/BudgetChangelog.cs

@@ -0,0 +1,28 @@
+using SolutionErp.Domain.Common;
+using SolutionErp.Domain.Contracts;   // reuse ChangelogAction
+
+namespace SolutionErp.Domain.Budgets;
+
+// Audit log unified cho mọi thay đổi trên ngân sách.
+public class BudgetChangelog : BaseEntity
+{
+    public Guid BudgetId { get; set; }
+    public Budget? Budget { get; set; }
+
+    public BudgetEntityType EntityType { get; set; }
+    public Guid? EntityId { get; set; }
+    public ChangelogAction Action { get; set; }
+    public BudgetPhase? PhaseAtChange { get; set; }
+    public Guid? UserId { get; set; }
+    public string? UserName { get; set; }
+    public string? Summary { get; set; }
+    public string? FieldChangesJson { get; set; }
+    public string? ContextNote { get; set; }
+}
+
+public enum BudgetEntityType
+{
+    Header = 1,
+    Detail = 2,
+    Workflow = 3,
+}

src/Backend/SolutionErp.Domain/Budgets/BudgetDetail.cs

@@ -0,0 +1,22 @@
+using SolutionErp.Domain.Common;
+
+namespace SolutionErp.Domain.Budgets;
+
+// Chi tiết ngân sách — pattern flat row giống PurchaseEvaluationDetail.
+// Group A.I/A.II/... cho hạng mục cha, NoiDung cho item con.
+public class BudgetDetail : BaseEntity
+{
+    public Guid BudgetId { get; set; }
+    public string GroupCode { get; set; } = string.Empty;    // "A.I", "A.II", ...
+    public string GroupName { get; set; } = string.Empty;    // "Bê tông", "Phụ gia", ...
+    public string? ItemCode { get; set; }
+    public string NoiDung { get; set; } = string.Empty;
+    public string? DonViTinh { get; set; }
+    public decimal KhoiLuong { get; set; }
+    public decimal DonGia { get; set; }
+    public decimal ThanhTien { get; set; }                   // = KhoiLuong × DonGia (hoặc nhập tay)
+    public int Order { get; set; }
+    public string? GhiChu { get; set; }
+
+    public Budget? Budget { get; set; }
+}

src/Backend/SolutionErp.Domain/Budgets/BudgetPhase.cs

@@ -0,0 +1,14 @@
+namespace SolutionErp.Domain.Budgets;
+
+// State machine ngân sách — đơn giản 3 bước duyệt + 2 terminal.
+//   DangSoanThao → ChoCCM → ChoCEO → DaDuyet
+//   Bất kỳ phase duyệt → DangSoanThao (reject)
+//   DangSoanThao → TuChoi
+public enum BudgetPhase
+{
+    DangSoanThao = 1,
+    ChoCCM = 2,
+    ChoCEO = 3,
+    DaDuyet = 4,
+    TuChoi = 99,
+}

src/Backend/SolutionErp.Domain/Budgets/BudgetPolicy.cs

@@ -0,0 +1,63 @@
+using SolutionErp.Domain.Identity;
+
+namespace SolutionErp.Domain.Budgets;
+
+// Policy hardcoded đơn giản — chưa versioned (theo user "tạm thời simple
+// default"). Tương lai nếu admin cần config qua UI: thêm BudgetWorkflow
+// Definition tables tương tự PE workflow.
+public sealed record BudgetPolicy(
+    string Name,
+    string Description,
+    IReadOnlyDictionary<(BudgetPhase From, BudgetPhase To), string[]> Transitions,
+    IReadOnlyDictionary<BudgetPhase, TimeSpan?> PhaseSla,
+    IReadOnlyList<BudgetPhase> ActivePhases)
+{
+    public bool HasPhase(BudgetPhase phase) => ActivePhases.Contains(phase);
+
+    public bool IsTransitionAllowed(
+        BudgetPhase from, BudgetPhase to,
+        IReadOnlyList<string> actorRoles)
+    {
+        if (!Transitions.TryGetValue((from, to), out var roles)) return false;
+        return actorRoles.Any(r => roles.Contains(r));
+    }
+
+    public IReadOnlyList<BudgetPhase> NextPhasesFrom(BudgetPhase from) =>
+        Transitions.Keys.Where(k => k.From == from).Select(k => k.To).Distinct().ToList();
+}
+
+public static class BudgetPolicies
+{
+    private static readonly Dictionary<BudgetPhase, TimeSpan?> DefaultSla = new()
+    {
+        [BudgetPhase.DangSoanThao] = TimeSpan.FromDays(5),
+        [BudgetPhase.ChoCCM] = TimeSpan.FromDays(3),
+        [BudgetPhase.ChoCEO] = TimeSpan.FromDays(2),
+        [BudgetPhase.DaDuyet] = null,
+        [BudgetPhase.TuChoi] = null,
+    };
+
+    public static readonly BudgetPolicy Default = new(
+        Name: "Default",
+        Description: "Quy trình ngân sách 3-step (Drafter → CCM → CEO).",
+        Transitions: new Dictionary<(BudgetPhase, BudgetPhase), string[]>
+        {
+            [(BudgetPhase.DangSoanThao, BudgetPhase.ChoCCM)] = [AppRoles.Drafter, AppRoles.DeptManager],
+            [(BudgetPhase.DangSoanThao, BudgetPhase.TuChoi)] = [AppRoles.Drafter, AppRoles.DeptManager],
+
+            [(BudgetPhase.ChoCCM, BudgetPhase.ChoCEO)] = [AppRoles.CostControl],
+            [(BudgetPhase.ChoCCM, BudgetPhase.DangSoanThao)] = [AppRoles.CostControl],
+
+            [(BudgetPhase.ChoCEO, BudgetPhase.DaDuyet)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
+            [(BudgetPhase.ChoCEO, BudgetPhase.DangSoanThao)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
+        },
+        PhaseSla: DefaultSla,
+        ActivePhases:
+        [
+            BudgetPhase.DangSoanThao,
+            BudgetPhase.ChoCCM,
+            BudgetPhase.ChoCEO,
+            BudgetPhase.DaDuyet,
+            BudgetPhase.TuChoi,
+        ]);
+}

src/Backend/SolutionErp.Domain/Contracts/Contract.cs

@@ -23,6 +23,7 @@ public class Contract : AuditableEntity
     public DateTime? SlaDeadline { get; set; }                     // Hết hạn phase hiện tại
     public string? DraftData { get; set; }                         // JSON field values (render template)
     public bool SlaWarningSent { get; set; }                       // Flag để không gửi warning 2 lần
+    public Guid? BudgetId { get; set; }                            // Reference Budget (Phase 7) — đối chiếu chi phí HĐ vs ngân sách
 
     public List<ContractApproval> Approvals { get; set; } = new();
     public List<ContractComment> Comments { get; set; } = new();

src/Backend/SolutionErp.Domain/Identity/MenuKeys.cs

@@ -51,6 +51,15 @@ public static class MenuKeys
     public const string PurchaseEvaluations = "PurchaseEvaluations";          // root group
     public const string PeWorkflows = "PeWorkflows";                           // workflow admin root
 
+    // ============================================================
+    // Module Ngân sách (Phase 7) — 4 bảng quản lý ngân sách dự án/gói thầu.
+    // 1 root + 3 leaf action (Danh sách / Thao tác / Duyệt).
+    // ============================================================
+    public const string Budgets = "Budgets";
+    public const string BudgetList = "Bg_List";
+    public const string BudgetCreate = "Bg_Create";
+    public const string BudgetPending = "Bg_Pending";
+
     public static readonly string[] PurchaseEvaluationTypeCodes =
         ["DuyetNcc", "DuyetNccPhuongAn"];
 
@@ -70,6 +79,7 @@ public static class MenuKeys
         Catalogs, CatalogUnits, CatalogMaterials, CatalogServices, CatalogWorkItems,
         Contracts, Forms, Reports,
         PurchaseEvaluations,
+        Budgets, BudgetList, BudgetCreate, BudgetPending,
         System, Users, Roles, Permissions, Workflows, PeWorkflows,
     ];
 

src/Backend/SolutionErp.Domain/PurchaseEvaluations/PurchaseEvaluation.cs

@@ -26,6 +26,7 @@ public class PurchaseEvaluation : AuditableEntity
     public string? PaymentTerms { get; set; }                        // JSON {tamUng, thanhToanTam, quyetToan, baoHanh, hanMucCongNo, danhGia}
 
     public Guid? ContractId { get; set; }                            // FK Contracts — set khi user gen HĐ từ phiếu
+    public Guid? BudgetId { get; set; }                              // FK Budget (Phase 7) — đối chiếu báo giá vs ngân sách gói thầu
 
     public List<PurchaseEvaluationSupplier> Suppliers { get; set; } = new();
     public List<PurchaseEvaluationDetail> Details { get; set; } = new();

src/Backend/SolutionErp.Infrastructure/Persistence/ApplicationDbContext.cs

@@ -1,6 +1,7 @@
 using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore;
 using SolutionErp.Application.Common.Interfaces;
+using SolutionErp.Domain.Budgets;
 using SolutionErp.Domain.Contracts;
 using SolutionErp.Domain.Contracts.Details;
 using SolutionErp.Domain.Forms;
@@ -59,6 +60,12 @@ public class ApplicationDbContext
     public DbSet<PurchaseEvaluationWorkflowStepApprover> PurchaseEvaluationWorkflowStepApprovers => Set<PurchaseEvaluationWorkflowStepApprover>();
     public DbSet<PurchaseEvaluationCodeSequence> PurchaseEvaluationCodeSequences => Set<PurchaseEvaluationCodeSequence>();
 
+    // Module Ngân sách (Phase 7) — 4 bảng: Budget header + Details + Approvals + Changelogs.
+    public DbSet<Budget> Budgets => Set<Budget>();
+    public DbSet<BudgetDetail> BudgetDetails => Set<BudgetDetail>();
+    public DbSet<BudgetApproval> BudgetApprovals => Set<BudgetApproval>();
+    public DbSet<BudgetChangelog> BudgetChangelogs => Set<BudgetChangelog>();
+
     protected override void OnModelCreating(ModelBuilder builder)
     {
         base.OnModelCreating(builder);

src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/BudgetConfiguration.cs

@@ -0,0 +1,89 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SolutionErp.Domain.Budgets;
+
+namespace SolutionErp.Infrastructure.Persistence.Configurations;
+
+public class BudgetConfiguration : IEntityTypeConfiguration<Budget>
+{
+    public void Configure(EntityTypeBuilder<Budget> b)
+    {
+        b.ToTable("Budgets");
+        b.HasKey(x => x.Id);
+
+        b.Property(x => x.MaNganSach).HasMaxLength(100);
+        b.Property(x => x.TenNganSach).HasMaxLength(500).IsRequired();
+        b.Property(x => x.Description).HasMaxLength(2000);
+        b.Property(x => x.Phase).HasConversion<int>();
+        b.Property(x => x.TongNganSach).HasPrecision(18, 2);
+
+        b.HasIndex(x => x.MaNganSach).IsUnique().HasFilter("[MaNganSach] IS NOT NULL");
+        b.HasIndex(x => new { x.Phase, x.IsDeleted });
+        b.HasIndex(x => x.ProjectId);
+        b.HasIndex(x => x.NamNganSach);
+        b.HasIndex(x => x.SlaDeadline);
+
+        b.HasMany(x => x.Details).WithOne(d => d.Budget).HasForeignKey(d => d.BudgetId).OnDelete(DeleteBehavior.Cascade);
+        b.HasMany(x => x.Approvals).WithOne(a => a.Budget).HasForeignKey(a => a.BudgetId).OnDelete(DeleteBehavior.Cascade);
+        b.HasMany(x => x.Changelogs).WithOne(c => c.Budget).HasForeignKey(c => c.BudgetId).OnDelete(DeleteBehavior.Cascade);
+
+        b.HasQueryFilter(x => !x.IsDeleted);
+    }
+}
+
+public class BudgetDetailConfiguration : IEntityTypeConfiguration<BudgetDetail>
+{
+    public void Configure(EntityTypeBuilder<BudgetDetail> b)
+    {
+        b.ToTable("BudgetDetails");
+        b.HasKey(x => x.Id);
+
+        b.Property(x => x.GroupCode).HasMaxLength(50).IsRequired();
+        b.Property(x => x.GroupName).HasMaxLength(200).IsRequired();
+        b.Property(x => x.ItemCode).HasMaxLength(100);
+        b.Property(x => x.NoiDung).HasMaxLength(500).IsRequired();
+        b.Property(x => x.DonViTinh).HasMaxLength(50);
+        b.Property(x => x.GhiChu).HasMaxLength(1000);
+        b.Property(x => x.KhoiLuong).HasPrecision(18, 4);
+        b.Property(x => x.DonGia).HasPrecision(18, 2);
+        b.Property(x => x.ThanhTien).HasPrecision(18, 2);
+
+        b.HasIndex(x => new { x.BudgetId, x.Order });
+    }
+}
+
+public class BudgetApprovalConfiguration : IEntityTypeConfiguration<BudgetApproval>
+{
+    public void Configure(EntityTypeBuilder<BudgetApproval> b)
+    {
+        b.ToTable("BudgetApprovals");
+        b.HasKey(x => x.Id);
+
+        b.Property(x => x.FromPhase).HasConversion<int>();
+        b.Property(x => x.ToPhase).HasConversion<int>();
+        b.Property(x => x.Decision).HasConversion<int>();
+        b.Property(x => x.Comment).HasMaxLength(1000);
+
+        b.HasIndex(x => new { x.BudgetId, x.ApprovedAt });
+    }
+}
+
+public class BudgetChangelogConfiguration : IEntityTypeConfiguration<BudgetChangelog>
+{
+    public void Configure(EntityTypeBuilder<BudgetChangelog> b)
+    {
+        b.ToTable("BudgetChangelogs");
+        b.HasKey(x => x.Id);
+
+        b.Property(x => x.EntityType).HasConversion<int>();
+        b.Property(x => x.Action).HasConversion<int>();
+        b.Property(x => x.PhaseAtChange).HasConversion<int>();
+        b.Property(x => x.UserName).HasMaxLength(200);
+        b.Property(x => x.Summary).HasMaxLength(500);
+        b.Property(x => x.ContextNote).HasMaxLength(2000);
+        b.Property(x => x.FieldChangesJson).HasColumnType("nvarchar(max)");
+
+        b.HasIndex(x => new { x.BudgetId, x.CreatedAt });
+        b.HasIndex(x => new { x.BudgetId, x.EntityType });
+    }
+}

src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/ContractConfiguration.cs

@@ -24,6 +24,7 @@ public class ContractConfiguration : IEntityTypeConfiguration<Contract>
         b.HasIndex(x => x.SupplierId);
         b.HasIndex(x => x.ProjectId);
         b.HasIndex(x => x.SlaDeadline);
+        b.HasIndex(x => x.BudgetId);
 
         b.HasMany(x => x.Approvals).WithOne(a => a.Contract).HasForeignKey(a => a.ContractId).OnDelete(DeleteBehavior.Cascade);
         b.HasMany(x => x.Comments).WithOne(c => c.Contract).HasForeignKey(c => c.ContractId).OnDelete(DeleteBehavior.Cascade);

src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/PurchaseEvaluationConfiguration.cs

@@ -25,6 +25,7 @@ public class PurchaseEvaluationConfiguration : IEntityTypeConfiguration<Purchase
         b.HasIndex(x => x.SlaDeadline);
         b.HasIndex(x => x.WorkflowDefinitionId);
         b.HasIndex(x => x.ContractId);
+        b.HasIndex(x => x.BudgetId);
 
         b.HasMany(x => x.Suppliers).WithOne(s => s.PurchaseEvaluation).HasForeignKey(s => s.PurchaseEvaluationId).OnDelete(DeleteBehavior.Cascade);
         b.HasMany(x => x.Details).WithOne(d => d.PurchaseEvaluation).HasForeignKey(d => d.PurchaseEvaluationId).OnDelete(DeleteBehavior.Cascade);

src/Backend/SolutionErp.Infrastructure/Persistence/DbInitializer.cs

@@ -1308,6 +1308,11 @@ public static class DbInitializer
             // Module Duyệt NCC (tiền-HĐ)
             (MenuKeys.PurchaseEvaluations, "Quy trình chọn Thầu phụ - NCC", null, 25, "ClipboardCheck"),
             (MenuKeys.PeWorkflows,         "Quy trình Duyệt NCC",           MenuKeys.System,  95, "GitCompareArrows"),
+            // Module Ngân sách (Phase 7)
+            (MenuKeys.Budgets,       "Ngân sách",           null,            27, "Wallet"),
+            (MenuKeys.BudgetList,    "Danh sách",           MenuKeys.Budgets, 1, "List"),
+            (MenuKeys.BudgetCreate,  "Thao tác",            MenuKeys.Budgets, 2, "Plus"),
+            (MenuKeys.BudgetPending, "Duyệt",               MenuKeys.Budgets, 3, "CheckCircle2"),
         };
 
         // Per-type sub-menu under Contracts: 1 group + 3 leaves each

src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260428043508_AddBudgets.cs

@@ -0,0 +1,236 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SolutionErp.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddBudgets : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<Guid>(
+                name: "BudgetId",
+                table: "PurchaseEvaluations",
+                type: "uniqueidentifier",
+                nullable: true);
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "BudgetId",
+                table: "Contracts",
+                type: "uniqueidentifier",
+                nullable: true);
+
+            migrationBuilder.CreateTable(
+                name: "Budgets",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    MaNganSach = table.Column<string>(type: "nvarchar(100)", maxLength: 100, nullable: true),
+                    TenNganSach = table.Column<string>(type: "nvarchar(500)", maxLength: 500, nullable: false),
+                    Description = table.Column<string>(type: "nvarchar(2000)", maxLength: 2000, nullable: true),
+                    NamNganSach = table.Column<int>(type: "int", nullable: false),
+                    ProjectId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    DepartmentId = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    DrafterUserId = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    Phase = table.Column<int>(type: "int", nullable: false),
+                    TongNganSach = table.Column<decimal>(type: "decimal(18,2)", precision: 18, scale: 2, nullable: false),
+                    SlaDeadline = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    SlaWarningSent = table.Column<bool>(type: "bit", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    IsDeleted = table.Column<bool>(type: "bit", nullable: false),
+                    DeletedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    DeletedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Budgets", x => x.Id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "BudgetApprovals",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    BudgetId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    FromPhase = table.Column<int>(type: "int", nullable: false),
+                    ToPhase = table.Column<int>(type: "int", nullable: false),
+                    ApproverUserId = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    Decision = table.Column<int>(type: "int", nullable: false),
+                    Comment = table.Column<string>(type: "nvarchar(1000)", maxLength: 1000, nullable: true),
+                    ApprovedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_BudgetApprovals", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_BudgetApprovals_Budgets_BudgetId",
+                        column: x => x.BudgetId,
+                        principalTable: "Budgets",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "BudgetChangelogs",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    BudgetId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    EntityType = table.Column<int>(type: "int", nullable: false),
+                    EntityId = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    Action = table.Column<int>(type: "int", nullable: false),
+                    PhaseAtChange = table.Column<int>(type: "int", nullable: true),
+                    UserId = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UserName = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: true),
+                    Summary = table.Column<string>(type: "nvarchar(500)", maxLength: 500, nullable: true),
+                    FieldChangesJson = table.Column<string>(type: "nvarchar(max)", nullable: true),
+                    ContextNote = table.Column<string>(type: "nvarchar(2000)", maxLength: 2000, nullable: true),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_BudgetChangelogs", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_BudgetChangelogs_Budgets_BudgetId",
+                        column: x => x.BudgetId,
+                        principalTable: "Budgets",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "BudgetDetails",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    BudgetId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    GroupCode = table.Column<string>(type: "nvarchar(50)", maxLength: 50, nullable: false),
+                    GroupName = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: false),
+                    ItemCode = table.Column<string>(type: "nvarchar(100)", maxLength: 100, nullable: true),
+                    NoiDung = table.Column<string>(type: "nvarchar(500)", maxLength: 500, nullable: false),
+                    DonViTinh = table.Column<string>(type: "nvarchar(50)", maxLength: 50, nullable: true),
+                    KhoiLuong = table.Column<decimal>(type: "decimal(18,4)", precision: 18, scale: 4, nullable: false),
+                    DonGia = table.Column<decimal>(type: "decimal(18,2)", precision: 18, scale: 2, nullable: false),
+                    ThanhTien = table.Column<decimal>(type: "decimal(18,2)", precision: 18, scale: 2, nullable: false),
+                    Order = table.Column<int>(type: "int", nullable: false),
+                    GhiChu = table.Column<string>(type: "nvarchar(1000)", maxLength: 1000, nullable: true),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_BudgetDetails", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_BudgetDetails_Budgets_BudgetId",
+                        column: x => x.BudgetId,
+                        principalTable: "Budgets",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PurchaseEvaluations_BudgetId",
+                table: "PurchaseEvaluations",
+                column: "BudgetId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Contracts_BudgetId",
+                table: "Contracts",
+                column: "BudgetId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_BudgetApprovals_BudgetId_ApprovedAt",
+                table: "BudgetApprovals",
+                columns: new[] { "BudgetId", "ApprovedAt" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_BudgetChangelogs_BudgetId_CreatedAt",
+                table: "BudgetChangelogs",
+                columns: new[] { "BudgetId", "CreatedAt" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_BudgetChangelogs_BudgetId_EntityType",
+                table: "BudgetChangelogs",
+                columns: new[] { "BudgetId", "EntityType" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_BudgetDetails_BudgetId_Order",
+                table: "BudgetDetails",
+                columns: new[] { "BudgetId", "Order" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Budgets_MaNganSach",
+                table: "Budgets",
+                column: "MaNganSach",
+                unique: true,
+                filter: "[MaNganSach] IS NOT NULL");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Budgets_NamNganSach",
+                table: "Budgets",
+                column: "NamNganSach");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Budgets_Phase_IsDeleted",
+                table: "Budgets",
+                columns: new[] { "Phase", "IsDeleted" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Budgets_ProjectId",
+                table: "Budgets",
+                column: "ProjectId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Budgets_SlaDeadline",
+                table: "Budgets",
+                column: "SlaDeadline");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "BudgetApprovals");
+
+            migrationBuilder.DropTable(
+                name: "BudgetChangelogs");
+
+            migrationBuilder.DropTable(
+                name: "BudgetDetails");
+
+            migrationBuilder.DropTable(
+                name: "Budgets");
+
+            migrationBuilder.DropIndex(
+                name: "IX_PurchaseEvaluations_BudgetId",
+                table: "PurchaseEvaluations");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Contracts_BudgetId",
+                table: "Contracts");
+
+            migrationBuilder.DropColumn(
+                name: "BudgetId",
+                table: "PurchaseEvaluations");
+
+            migrationBuilder.DropColumn(
+                name: "BudgetId",
+                table: "Contracts");
+        }
+    }
+}

src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/ApplicationDbContextModelSnapshot.cs

@@ -125,12 +125,274 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.ToTable("UserTokens", (string)null);
                 });
 
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.Budget", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("DeletedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid?>("DepartmentId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Description")
+                        .HasMaxLength(2000)
+                        .HasColumnType("nvarchar(2000)");
+
+                    b.Property<Guid?>("DrafterUserId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<bool>("IsDeleted")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("MaNganSach")
+                        .HasMaxLength(100)
+                        .HasColumnType("nvarchar(100)");
+
+                    b.Property<int>("NamNganSach")
+                        .HasColumnType("int");
+
+                    b.Property<int>("Phase")
+                        .HasColumnType("int");
+
+                    b.Property<Guid>("ProjectId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("SlaDeadline")
+                        .HasColumnType("datetime2");
+
+                    b.Property<bool>("SlaWarningSent")
+                        .HasColumnType("bit");
+
+                    b.Property<string>("TenNganSach")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("nvarchar(500)");
+
+                    b.Property<decimal>("TongNganSach")
+                        .HasPrecision(18, 2)
+                        .HasColumnType("decimal(18,2)");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("MaNganSach")
+                        .IsUnique()
+                        .HasFilter("[MaNganSach] IS NOT NULL");
+
+                    b.HasIndex("NamNganSach");
+
+                    b.HasIndex("ProjectId");
+
+                    b.HasIndex("SlaDeadline");
+
+                    b.HasIndex("Phase", "IsDeleted");
+
+                    b.ToTable("Budgets", (string)null);
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.BudgetApproval", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("ApprovedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("ApproverUserId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("BudgetId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Comment")
+                        .HasMaxLength(1000)
+                        .HasColumnType("nvarchar(1000)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<int>("Decision")
+                        .HasColumnType("int");
+
+                    b.Property<int>("FromPhase")
+                        .HasColumnType("int");
+
+                    b.Property<int>("ToPhase")
+                        .HasColumnType("int");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("BudgetId", "ApprovedAt");
+
+                    b.ToTable("BudgetApprovals", (string)null);
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.BudgetChangelog", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<int>("Action")
+                        .HasColumnType("int");
+
+                    b.Property<Guid>("BudgetId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("ContextNote")
+                        .HasMaxLength(2000)
+                        .HasColumnType("nvarchar(2000)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid?>("EntityId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<int>("EntityType")
+                        .HasColumnType("int");
+
+                    b.Property<string>("FieldChangesJson")
+                        .HasColumnType("nvarchar(max)");
+
+                    b.Property<int?>("PhaseAtChange")
+                        .HasColumnType("int");
+
+                    b.Property<string>("Summary")
+                        .HasMaxLength(500)
+                        .HasColumnType("nvarchar(500)");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid?>("UserId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("UserName")
+                        .HasMaxLength(200)
+                        .HasColumnType("nvarchar(200)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("BudgetId", "CreatedAt");
+
+                    b.HasIndex("BudgetId", "EntityType");
+
+                    b.ToTable("BudgetChangelogs", (string)null);
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.BudgetDetail", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("BudgetId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<decimal>("DonGia")
+                        .HasPrecision(18, 2)
+                        .HasColumnType("decimal(18,2)");
+
+                    b.Property<string>("DonViTinh")
+                        .HasMaxLength(50)
+                        .HasColumnType("nvarchar(50)");
+
+                    b.Property<string>("GhiChu")
+                        .HasMaxLength(1000)
+                        .HasColumnType("nvarchar(1000)");
+
+                    b.Property<string>("GroupCode")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("nvarchar(50)");
+
+                    b.Property<string>("GroupName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("nvarchar(200)");
+
+                    b.Property<string>("ItemCode")
+                        .HasMaxLength(100)
+                        .HasColumnType("nvarchar(100)");
+
+                    b.Property<decimal>("KhoiLuong")
+                        .HasPrecision(18, 4)
+                        .HasColumnType("decimal(18,4)");
+
+                    b.Property<string>("NoiDung")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("nvarchar(500)");
+
+                    b.Property<int>("Order")
+                        .HasColumnType("int");
+
+                    b.Property<decimal>("ThanhTien")
+                        .HasPrecision(18, 2)
+                        .HasColumnType("decimal(18,2)");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("BudgetId", "Order");
+
+                    b.ToTable("BudgetDetails", (string)null);
+                });
+
             modelBuilder.Entity("SolutionErp.Domain.Contracts.Contract", b =>
                 {
                     b.Property<Guid>("Id")
                         .ValueGeneratedOnAdd()
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<Guid?>("BudgetId")
+                        .HasColumnType("uniqueidentifier");
+
                     b.Property<bool>("BypassProcurementAndCCM")
                         .HasColumnType("bit");
 
@@ -206,6 +468,8 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("BudgetId");
+
                     b.HasIndex("MaHopDong")
                         .IsUnique()
                         .HasFilter("[MaHopDong] IS NOT NULL");
@@ -1910,6 +2174,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                         .ValueGeneratedOnAdd()
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<Guid?>("BudgetId")
+                        .HasColumnType("uniqueidentifier");
+
                     b.Property<Guid?>("ContractId")
                         .HasColumnType("uniqueidentifier");
 
@@ -1983,6 +2250,8 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("BudgetId");
+
                     b.HasIndex("ContractId");
 
                     b.HasIndex("MaPhieu")
@@ -2558,6 +2827,39 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                         .IsRequired();
                 });
 
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.BudgetApproval", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.Budgets.Budget", "Budget")
+                        .WithMany("Approvals")
+                        .HasForeignKey("BudgetId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Budget");
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.BudgetChangelog", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.Budgets.Budget", "Budget")
+                        .WithMany("Changelogs")
+                        .HasForeignKey("BudgetId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Budget");
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.BudgetDetail", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.Budgets.Budget", "Budget")
+                        .WithMany("Details")
+                        .HasForeignKey("BudgetId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Budget");
+                });
+
             modelBuilder.Entity("SolutionErp.Domain.Contracts.ContractApproval", b =>
                 {
                     b.HasOne("SolutionErp.Domain.Contracts.Contract", "Contract")
@@ -2838,6 +3140,15 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Navigation("Step");
                 });
 
+            modelBuilder.Entity("SolutionErp.Domain.Budgets.Budget", b =>
+                {
+                    b.Navigation("Approvals");
+
+                    b.Navigation("Changelogs");
+
+                    b.Navigation("Details");
+                });
+
             modelBuilder.Entity("SolutionErp.Domain.Contracts.Contract", b =>
                 {
                     b.Navigation("Approvals");