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)

backend/apps/accounts/views.py

@@ -0,0 +1,36 @@
+from django.contrib.auth import get_user_model
+from rest_framework import generics, permissions, status
+from rest_framework.response import Response
+from rest_framework.views import APIView
+
+from .serializers import ChangePasswordSerializer, RegisterSerializer, UserSerializer
+
+UserModel = get_user_model()
+
+
+class RegisterView(generics.CreateAPIView):
+    """Create a new user account."""
+    queryset = UserModel.objects.all()
+    serializer_class = RegisterSerializer
+    permission_classes = [permissions.AllowAny]
+
+
+class UserDetailView(generics.RetrieveUpdateAPIView):
+    """Get or update the authenticated user's profile."""
+    serializer_class = UserSerializer
+    permission_classes = [permissions.IsAuthenticated]
+
+    def get_object(self):
+        return self.request.user
+
+
+class ChangePasswordView(APIView):
+    """Change the authenticated user's password."""
+    permission_classes = [permissions.IsAuthenticated]
+
+    def post(self, request):
+        serializer = ChangePasswordSerializer(data=request.data, context={"request": request})
+        serializer.is_valid(raise_exception=True)
+        request.user.set_password(serializer.validated_data["new_password"])
+        request.user.save()
+        return Response({"detail": "Password changed successfully."}, status=status.HTTP_200_OK)