[CLAUDE] Phase1: foundation - BE Clean Arch + Identity + JWT + 2 FE React + login E2E

Backend (.NET 10):
- Domain: BaseEntity/AuditableEntity, ContractType/Phase/ApprovalDecision enums, User/Role (Identity<Guid>), AppRoles (12 const)
- Application: IApplicationDbContext/ICurrentUser/IDateTime/IJwtTokenService, custom exceptions, ValidationBehavior (MediatR pipeline), Auth CQRS (Login/Refresh/Me), DependencyInjection
- Infrastructure: ApplicationDbContext (IdentityDbContext), AuditingInterceptor (auto audit + soft delete), DbInitializer (seed 12 role + admin), DesignTimeDbContextFactory, JwtTokenService, DateTimeService, DI
- Api: CurrentUserService, GlobalExceptionMiddleware (ProblemDetails), AuthController, Program.cs rewrite (Serilog + JWT + CORS + Swagger), appsettings + launchSettings (port 5443)
- Migration Init applied to SolutionErp_Dev LocalDB

Frontend (React 19 + Vite 8 + Tailwind 4):
- fe-admin (:8082 blue) + fe-user (:8080 emerald) - shared structure, khac menu + brand color
- Tailwind 4 via @tailwindcss/vite plugin, theme brand colors
- AuthContext (localStorage token), ProtectedRoute, Layout (sidebar + header)
- UI kit: Button/Input/Label (CVA + Tailwind)
- LoginPage voi toast error, DashboardPage/InboxPage placeholder
- Axios interceptor: auto Bearer + 401 redirect
- TanStack Query client, React Router 7, Sonner toast

Package downgrades (do .NET 10 / TS 6 compat):
- MediatR 14 -> 12.4.1 (v14 breaking changes)
- Swashbuckle 10 -> 6.9.0 (v10 khong tuong thich OpenApi 2)
- Removed Microsoft.AspNetCore.OpenApi (conflict voi Swashbuckle)

E2E verified: POST /api/auth/login qua Vite proxy ca 2 FE -> JWT + user info

Credentials seed: admin@solutionerp.local / Admin@123456

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

fe-admin/src/components/ui/Button.tsx

@@ -0,0 +1,33 @@
+import { forwardRef, type ButtonHTMLAttributes } from 'react'
+import { cva, type VariantProps } from 'class-variance-authority'
+import { cn } from '@/lib/cn'
+
+const buttonVariants = cva(
+  'inline-flex items-center justify-center gap-2 rounded-md text-sm font-medium transition disabled:pointer-events-none disabled:opacity-50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-offset-1 focus-visible:ring-brand-500',
+  {
+    variants: {
+      variant: {
+        primary: 'bg-brand-600 text-white hover:bg-brand-700',
+        secondary: 'bg-slate-200 text-slate-900 hover:bg-slate-300',
+        outline: 'border border-slate-300 bg-white hover:bg-slate-50',
+        ghost: 'hover:bg-slate-100',
+        danger: 'bg-red-600 text-white hover:bg-red-700',
+      },
+      size: {
+        sm: 'h-8 px-3',
+        md: 'h-10 px-4',
+        lg: 'h-11 px-6 text-base',
+      },
+    },
+    defaultVariants: { variant: 'primary', size: 'md' },
+  },
+)
+
+type Props = ButtonHTMLAttributes<HTMLButtonElement> & VariantProps<typeof buttonVariants>
+
+export const Button = forwardRef<HTMLButtonElement, Props>(
+  ({ className, variant, size, ...props }, ref) => (
+    <button ref={ref} className={cn(buttonVariants({ variant, size }), className)} {...props} />
+  ),
+)
+Button.displayName = 'Button'