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/dependencies.py

@@ -0,0 +1,39 @@
+from typing import AsyncGenerator
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy import select
+from .database import AsyncSessionLocal
+from .models.user import User
+from .services.auth import decode_token
+
+bearer_scheme = HTTPBearer(auto_error=False)
+
+
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    async with AsyncSessionLocal() as session:
+        yield session
+
+
+async def get_current_user(
+    credentials: HTTPAuthorizationCredentials | None = Depends(bearer_scheme),
+    db: AsyncSession = Depends(get_db),
+) -> User:
+    if not credentials:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Not authenticated")
+
+    user_id = decode_token(credentials.credentials)
+    if not user_id:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token")
+
+    result = await db.execute(select(User).where(User.id == user_id, User.is_active == True))
+    user = result.scalar_one_or_none()
+    if not user:
+        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="User not found")
+    return user
+
+
+async def require_admin(current_user: User = Depends(get_current_user)) -> User:
+    if not current_user.is_admin:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Admin required")
+    return current_user