[CLAUDE] Docs+Skill: chốt Session 16 wrap-up — drastic refactor flat workflow (Chunk D)

Session 16 (2026-05-08) docs/skill/memory wrap-up:

STATUS.md:
- Last updated Session 16 (2 commit Chunk A+B)
- Phase summary count (20→21 mig, 96→77 test, 57→55 bảng)
- Recently Done row Session 16 chi tiết (drastic refactor hoàn tất)
- Phase enum simplified semantic post-Mig 21

HANDOFF.md:
- TL;DR Session 16 prepend với 2 chunk + Chunk C SKIP rationale
- Per-chunk implementation chi tiết (Domain + Mig 21 + Service + Tests
  + FE Designer)
- 8 cảnh báo Session 17+: UAT live test / old data migration / Sample
  seed / Budget N-stage / schema-diagram / skill refresh / tests flat /
  Hard blockers Ops

migration-todos.md: Phase 9 + Session 16 block 2 chunk done + 7 defer task

Session log NEW `2026-05-08-0500-drastic-refactor-flat-workflow.md`:
- Bối cảnh resume từ S15 defer
- Spec implementation (Phase enum, state machine, schema Mig 21)
- Per-chunk Chunk A + Chunk B detail
- Chunk C skip rationale
- Memory `feedback_drastic_refactor_scope` validation:
  scope estimate 30% accurate (3h actual vs 10h conservative)
- Plan organization sau S16

Skill ef-core-migration:
- description + heading: 20→21 migration
- + Mig 21 row "RefactorWorkflowToFlatModel" với detail (4 ALTER + 2
  ALTER + DROP TABLE × 2 + DROP COLUMN × 2 + restore simple unique × 2)
- Total 57→55 bảng (-2 InnerStep tables)
- Tests: 96→77 (drop 19 legacy)

CLAUDE.md root:
- Migration count 20→21
- DB tables 57→55
- Workflow flat description thay N-stage description

docs/rules.md §7: 96→77 test (Mig 21 simplified)

Memory `project_solution_erp.md`:
- Add "Tổng sau session 16" block với drastic refactor details

🎉 Session 16 wrap-up. Cumulative since session start (S15 wrap-up
`38d10b7`): 4 commit (S15 wrap-up was final S15) + 3 commit Session 16
(A `dbb0089` + B `88a5be1` + D current).

Defer Session 17+ priority:
1. UAT live test workflow flat (3 phòng × N cấp realistic)
2. Old PE/HĐ legacy phase data migration
3. Sample data seed (Task 2 carry-over)
4. Hard blockers Ops

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -50,7 +50,7 @@ Kiến trúc: **.NET 10 Clean Architecture + 2 React FE (admin + user) + SQL Ser
 - Audit fields: `CreatedAt`, `UpdatedAt`, `CreatedBy`, `UpdatedBy` (`BaseEntity`)
 - Soft delete: `IsDeleted`, `DeletedAt`, `DeletedBy` (`AuditableEntity`)
 - Migrations: `dotnet ef migrations add <Name> --project src/Backend/SolutionErp.Infrastructure --startup-project src/Backend/SolutionErp.Api`
-- **Hiện có 20 migration → 57 bảng** (Phase 9+ — Mig 18 `AddPeWorkflowInnerStepsAndPositionLevel` + Mig 19 `AlterPeDeptApprovalsUniqueFilteredForInnerSteps` + Mig 20 `AddContractWorkflowInnerStepsAndAlterDeptApprovalUnique`. N-stage workflow approval Phòng × PositionLevel cấu hình động per WorkflowStep cha. Mỗi inner step = 1 cấp duyệt sequential. Backward compat 100% với 2-stage Mig 16 qua filtered unique. PE 3-button Duyệt/Trả lại/Từ chối)
+- **Hiện có 21 migration → 55 bảng** (Phase 9+ — Mig 21 `RefactorWorkflowToFlatModel` DRASTIC REFACTOR Session 16. Bỏ phase enum legacy (2-9 + 98 deprecated giữ data cũ), dùng ChoDuyet=10 đơn nhất + CurrentWorkflowStepIndex tracking. Workflow flat list (Phòng × Cấp × Approvers). WorkflowStep + DepartmentId+PositionLevel. Drop InnerStep entities (Mig 18+20). Service rewrite iterate steps OrderBy Order, advance pointer per approve. Match approver Dept+PositionLevel OR Approvers Role/User. PE 3-button Duyệt forward / Trả lại smart-reject jump-back / Từ chối khoá phiếu)
 
 ### Modules
 
@@ -84,7 +84,7 @@ tests/
     └── Application/                  (6 test - PeWorkflowDefinition versioning)
 ```
 
-**96 unit test pass** / ~3s (54 Domain + 42 Infra: 17 codegen + 6 PE WF + 6 PE 2-stage + 6 PE N-stage S12 + 6 Contract N-stage S13 + 1 PE Reject Từ chối S14). CI gate + path filter live.
+**77 unit test pass** / ~3s (54 Domain + 23 Infra: 17 codegen + 6 PE WF versioning). Mig 21 drop 19 legacy N-stage/2-stage tests. CI gate + path filter live.
 
 ```bash
 dotnet test SolutionErp.slnx     # chạy cả 2 test project