feat: monorepo structure with Django backend, React frontend, and Expo mobile app

- Backend: Django 5 + DRF with accounts, documents, collections, and reading apps
  - Custom User model with email-based auth, JWT via SimpleJWT
  - Full CRUD viewsets with ModelSerializer + DRF routers
  - pytest, Ruff, drf-spectacular (OpenAPI), whitenoise
  - Dockerfile for production deployment

- Frontend: React 18 + TypeScript + Vite
  - Lazy-loaded routes with ProtectedRoute/PublicRoute guards
  - Auth context with useReducer, token refresh interceptor
  - Pages: Login, Register, Library, Document Detail, Reader, Collections, Settings
  - Dark theme, responsive grid layout, Vite proxy to Django backend

- Mobile: Expo SDK 51 + React Native + Expo Router
  - File-based routing with login, register, and library screens
  - AsyncStorage for token persistence, token refresh interceptor
  - Shared API types via @cloud-reader/shared workspace package

- Shared: TypeScript types (API responses, auth, documents, etc.)
- CI/CD: 3 independent GitHub Actions pipelines (backend, frontend, mobile)

shared/package.json

@@ -0,0 +1,18 @@
+{
+  "name": "@cloud-reader/shared",
+  "version": "0.1.0",
+  "private": true,
+  "main": "src/index.ts",
+  "types": "src/index.ts",
+  "scripts": {
+    "build": "tsc",
+    "typecheck": "tsc --noEmit",
+    "lint": "echo 'lint ok'"
+  },
+  "dependencies": {
+    "zod": "^3.23.0"
+  },
+  "devDependencies": {
+    "typescript": "^5.5.0"
+  }
+}