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)

frontend/package.json

@@ -0,0 +1,43 @@
+{
+  "name": "frontend",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start",
+    "lint": "eslint"
+  },
+  "dependencies": {
+    "class-variance-authority": "^0.7.1",
+    "clsx": "^2.1.1",
+    "lucide-react": "^0.576.0",
+    "next": "16.1.6",
+    "next-themes": "^0.4.6",
+    "radix-ui": "^1.4.3",
+    "react": "19.2.3",
+    "react-dom": "19.2.3",
+    "sonner": "^2.0.7",
+    "tailwind-merge": "^3.5.0"
+  },
+  "devDependencies": {
+    "@tailwindcss/postcss": "^4",
+    "@types/node": "^20",
+    "@types/react": "^19",
+    "@types/react-dom": "^19",
+    "eslint": "^9",
+    "eslint-config-next": "16.1.6",
+    "shadcn": "^3.8.5",
+    "tailwindcss": "^4",
+    "tw-animate-css": "^1.4.0",
+    "typescript": "^5"
+  },
+  "ignoreScripts": [
+    "sharp",
+    "unrs-resolver"
+  ],
+  "trustedDependencies": [
+    "sharp",
+    "unrs-resolver"
+  ]
+}