Initial commit: Phase 1 – Projektstruktur, DB-Schema, Core-API

- FastAPI-Backend mit vollständiger ABS v2.x API-Kompatibilität
- SQLAlchemy-Models: User, Library, LibraryItem, BookFile, Chapter,
  Podcast, PodcastEpisode, MediaProgress, Bookmark, PlaybackSession
- Auth: JWT-Login (/login, /logout, /api/authorize)
- Library + Items Endpoints inkl. camelCase ABS-Response-Format
- HLS-Streaming via FFmpeg (POST /api/items/:id/play, Session-Sync)
- Me/Progress Endpoints + Lesezeichen
- User-Management + Server-Settings (Admin)
- Library-Scanner (MP3/WAV Discovery, Hintergrund-Task)
- File Watcher (watchdog, 30s Debounce)
- Matching-Skelett (MusicBrainz, OpenLibrary, Google Books – Phase 5)
- Docker-Setup: backend (Python 3.12+FFmpeg), frontend (React/Vite),
  nginx Reverse-Proxy auf Port 3000
- setup.sh: Installiert Docker auf Debian/Ubuntu, richtet .env ein

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/database.py

@@ -0,0 +1,26 @@
+from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
+from sqlalchemy.orm import DeclarativeBase
+from .config import get_settings
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def create_engine_and_session():
+    settings = get_settings()
+    engine = create_async_engine(
+        settings.database_url,
+        connect_args={"check_same_thread": False},
+        echo=False,
+    )
+    session_factory = async_sessionmaker(engine, expire_on_commit=False, class_=AsyncSession)
+    return engine, session_factory
+
+
+engine, AsyncSessionLocal = create_engine_and_session()
+
+
+async def init_db():
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)