feat(domain): add core entities — Club, Member, WorkItem, Shift with state machine

- Create domain entities in WorkClub.Domain/Entities: Club, Member, WorkItem, Shift, ShiftSignup
- Implement enums: SportType, ClubRole, WorkItemStatus
- Add ITenantEntity interface for multi-tenancy support
- Implement state machine validation on WorkItem with C# 14 switch expressions
- Valid transitions: Open→Assigned→InProgress→Review→Done, Review→InProgress (rework)
- All invalid transitions throw InvalidOperationException
- TDD approach: Write tests first, 12/12 passing
- Use required properties with explicit Guid/Guid? for foreign keys
- DateTimeOffset for timestamps (timezone-aware, multi-tenant friendly)
- RowVersion byte[] for optimistic concurrency control
- No navigation properties yet (deferred to EF Core task)
- No domain events or validation attributes (YAGNI for MVP)

.sisyphus/evidence/task-5-nextjs-build.txt

@@ -0,0 +1,61 @@
+=== NEXT.JS 15 BUILD VERIFICATION ===
+Date: 2026-03-03
+Task: Initialize Next.js 15 project with TypeScript, Tailwind CSS, shadcn/ui
+
+BUILD COMMAND: bun run build
+BUILD STATUS: SUCCESS
+EXIT CODE: 0
+
+=== BUILD OUTPUT ===
+$ next build
+▲ Next.js 16.1.6 (Turbopack)
+
+  Creating an optimized production build ...
+✓ Compiled successfully in 2.9s
+  Running TypeScript ...
+  Collecting page data using 11 workers ...
+  Generating static pages using 11 workers (0/4) ...
+  Generating static pages using 11 workers (1/4) 
+  Generating static pages using 11 workers (2/4) 
+  Generating static pages using 11 workers (3/4) 
+✓ Generating static pages using 11 workers (4/4) in 240.4ms
+  Finalizing page optimization ...
+
+Route (app)
+┌ ○ /
+└ ○ /_not-found
+
+○  (Static)  prerendered as static content
+
+=== STANDALONE BUILD VERIFICATION ===
+✓ .next/standalone/ directory exists
+✓ .next/standalone/server.js exists (6553 bytes)
+✓ .next/standalone/package.json exists
+✓ .next/standalone/node_modules/ directory exists
+
+Configuration applied:
+- next.config.ts: output = 'standalone' ✓
+- tsconfig.json: paths aliases @/* → ./src/* ✓
+- All directory structure created: app/, components/, lib/, hooks/, types/ ✓
+
+Dependencies installed:
+- Next.js 16.1.6
+- React 19.2.3
+- React DOM 19.2.3
+- TypeScript 5.9.3
+- Tailwind CSS 4.2.1
+- ESLint 9.39.3
+
+shadcn/ui components installed:
+✓ button
+✓ card
+✓ badge
+✓ input
+✓ label
+✓ select
+✓ dialog
+✓ dropdown-menu
+✓ table
+✓ sonner (toast replacement)
+
+BUILD VERIFICATION: PASSED