chore: beta release v0.5.0-beta

- Bump version to 0.5.0-beta
- Add Apache-2.0 LICENSE (official text) + NOTICE
- Add Docker support: multi-stage Dockerfile + docker-compose
  * non-root user, tini PID 1, gunicorn + uvicorn workers
  * healthcheck, OCI labels, persistent /data volume
- Add GitHub Actions CI (lint/import-check + Docker smoke-test)
- Backend polish:
  * modern lifespan handler (replaces deprecated on_event)
  * explicit sort validation (400 instead of 500)
  * title min_length=1 schema validation
  * configurable data dir + http timeout via env
  * avg_rating helper extracted (DRY)
- Frontend polish:
  * beta badge in title, footer with live version
  * loading spinner on initial fetch
  * updated README, badges, config table, roadmap

app/database.py

@@ -1,15 +1,17 @@
 """Datenbank-Engine und Session-Verwaltung."""
+# SPDX-License-Identifier: Apache-2.0
 from __future__ import annotations
 
+import os
 from pathlib import Path
 
 from sqlalchemy import create_engine
 from sqlalchemy.orm import DeclarativeBase, sessionmaker
 
-# SQLite-Datei liegt im data/-Ordner (gitignored).
-BASE_DIR = Path(__file__).resolve().parent.parent
-DATA_DIR = BASE_DIR / "data"
-DATA_DIR.mkdir(exist_ok=True)
+# SQLite-Datei: überschreibbar via WATCHSTACK_DATA_DIR (für Docker)
+_BASE_DIR = Path(__file__).resolve().parent.parent
+DATA_DIR = Path(os.environ.get("WATCHSTACK_DATA_DIR", _BASE_DIR / "data"))
+DATA_DIR.mkdir(parents=True, exist_ok=True)
 DB_PATH = DATA_DIR / "watchstack.db"
 
 DATABASE_URL = f"sqlite:///{DB_PATH}"
@@ -39,7 +41,6 @@ def get_db():
 
 def init_db() -> None:
     """Erstellt alle Tabellen, falls noch nicht vorhanden."""
-    # noqa: F401 – Modelle müssen importiert sein, damit sie bei Base.metadata registriert sind.
-    from app import models  # type: ignore[F401]
+    from app import models  # noqa: F401 – registriert Modelle bei Base.metadata
 
     Base.metadata.create_all(bind=engine)