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/documents/admin.py

@@ -0,0 +1,11 @@
+from django.contrib import admin
+
+from .models import Document
+
+
+@admin.register(Document)
+class DocumentAdmin(admin.ModelAdmin):
+    list_display = ["title", "author", "file_type", "file_size", "is_public", "owner", "uploaded_at"]
+    list_filter = ["file_type", "is_public"]
+    search_fields = ["title", "author", "description"]
+    date_hierarchy = "uploaded_at"

backend/apps/documents/models.py

@@ -0,0 +1,48 @@
+from django.conf import settings
+from django.db import models
+
+
+class Document(models.Model):
+    """A digital document (ebook, PDF, etc.) uploaded by a user."""
+
+    class FileType(models.TextChoices):
+        PDF = "pdf", "PDF"
+        EPUB = "epub", "EPUB"
+        MOBI = "mobi", "MOBI"
+        TXT = "txt", "Plain Text"
+        DOCX = "docx", "Word Document"
+
+    title = models.CharField(max_length=500)
+    author = models.CharField(max_length=300, blank=True, null=True)
+    description = models.TextField(blank=True, default="")
+    cover = models.ImageField(upload_to="covers/", blank=True, null=True)
+    file = models.FileField(upload_to="documents/")
+    file_type = models.CharField(max_length=10, choices=FileType.choices)
+    file_size = models.PositiveIntegerField(help_text="File size in bytes")
+    page_count = models.PositiveIntegerField(blank=True, null=True)
+    tags = models.JSONField(default=list, blank=True)
+    is_public = models.BooleanField(default=False)
+    owner = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        related_name="documents",
+    )
+    uploaded_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        db_table = "documents_document"
+        ordering = ["-uploaded_at"]
+        indexes = [
+            models.Index(fields=["owner", "-uploaded_at"]),
+            models.Index(fields=["file_type"]),
+        ]
+
+    def __str__(self) -> str:
+        return self.title
+
+    @property
+    def cover_url(self) -> str | None:
+        if self.cover:
+            return self.cover.url
+        return None

backend/apps/documents/serializers.py

@@ -0,0 +1,41 @@
+from rest_framework import serializers
+
+from .models import Document
+
+
+class DocumentListSerializer(serializers.ModelSerializer[Document]):
+    cover_url = serializers.SerializerMethodField()
+
+    class Meta:
+        model = Document
+        fields = [
+            "id", "title", "author", "cover_url", "description",
+            "file_type", "file_size", "page_count", "tags",
+            "is_public", "uploaded_at", "updated_at",
+        ]
+        read_only_fields = ["id", "uploaded_at", "updated_at"]
+
+    def get_cover_url(self, obj: Document) -> str | None:
+        return obj.cover_url
+
+
+class DocumentDetailSerializer(DocumentListSerializer):
+    owner = serializers.PrimaryKeyRelatedField(read_only=True)
+
+    class Meta(DocumentListSerializer.Meta):
+        fields = DocumentListSerializer.Meta.fields + ["owner", "file"]
+
+
+class DocumentUploadSerializer(serializers.ModelSerializer[Document]):
+    class Meta:
+        model = Document
+        fields = [
+            "title", "author", "description", "cover", "file",
+            "file_type", "file_size", "page_count", "tags", "is_public",
+        ]
+
+    def validate_file_size(self, value: int) -> int:
+        max_size = 100 * 1024 * 1024  # 100 MB
+        if value > max_size:
+            raise serializers.ValidationError("File size must not exceed 100 MB.")
+        return value

backend/apps/documents/urls.py

@@ -0,0 +1,13 @@
+from django.urls import include, path
+from rest_framework.routers import DefaultRouter
+
+from . import views
+
+router = DefaultRouter()
+router.register("", views.DocumentViewSet, basename="document")
+
+app_name = "documents"
+
+urlpatterns = [
+    path("", include(router.urls)),
+]

backend/apps/documents/views.py

@@ -0,0 +1,35 @@
+from rest_framework import permissions, viewsets
+
+from .models import Document
+from .serializers import DocumentDetailSerializer, DocumentListSerializer, DocumentUploadSerializer
+
+
+class IsOwnerOrPublic(permissions.BasePermission):
+    """Allow access if user is owner or the document is public."""
+
+    def has_object_permission(self, request, view, obj: Document) -> bool:
+        if request.method in permissions.SAFE_METHODS:
+            return obj.is_public or obj.owner == request.user
+        return obj.owner == request.user
+
+
+class DocumentViewSet(viewsets.ModelViewSet):
+    """CRUD for documents with owner-scoping."""
+    permission_classes = [permissions.IsAuthenticated, IsOwnerOrPublic]
+
+    def get_serializer_class(self):
+        if self.action == "create":
+            return DocumentUploadSerializer
+        if self.action in ("retrieve", "update", "partial_update"):
+            return DocumentDetailSerializer
+        return DocumentListSerializer
+
+    def get_queryset(self):
+        user = self.request.user
+        qs = Document.objects.select_related("owner")
+        if self.action == "list":
+            return qs.filter(owner=user) | qs.filter(is_public=True)
+        return qs
+
+    def perform_create(self, serializer):
+        serializer.save(owner=self.request.user)