refactor: consolidate backend/frontend, remove api/web duplicates

- backend/ kept as canonical, api/ features merged (EBook, ReadingProgress, ReadingSettings)
- frontend/ kept as canonical, web/ pages merged (Library, Reader, AddBook, Auth, Settings)
- Added Dockerfiles for backend/ and frontend/
- Updated docker-compose.yml for consolidated services
- Updated README, package.json workspaces
- api/ and web/ directories removed

backend/apps/books/urls.py

@@ -1,11 +1,16 @@
 from django.urls import include, path
 from rest_framework.routers import DefaultRouter
 
-from apps.books.views import BookViewSet
+from apps.books.views import BookViewSet, EBookViewSet, ReadingSettingsViewSet
 
 router = DefaultRouter()
 router.register(r"", BookViewSet, basename="book")
 
+ebook_router = DefaultRouter()
+ebook_router.register(r"ebooks", EBookViewSet, basename="ebook")
+
 urlpatterns = [
     path("", include(router.urls)),
+    path("", include(ebook_router.urls)),
+    path("settings/", ReadingSettingsViewSet.as_view({"get": "list", "patch": "partial_update"}), name="reading-settings"),
 ]