Update-System: /api/version + /api/release-notes + RELEASES.json

Frontend kann jetzt erkennen, wann eine neue Version live ist, und dem Nutzer
einen passenden Hinweis sowie die Release-Notes anzeigen.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/routes/version_router.py

@@ -0,0 +1,54 @@
+"""Version + Release-Notes-Endpoints fuer das Frontend-Update-System."""
+import json
+import subprocess
+from datetime import datetime, timezone
+from pathlib import Path
+from fastapi import APIRouter
+
+REPO_ROOT = Path(__file__).resolve().parent.parent.parent
+RELEASES_FILE = REPO_ROOT / 'RELEASES.json'
+
+# Version-Hash beim Boot einmalig auslesen.
+try:
+    COMMIT_HASH = subprocess.check_output(
+        ['git', 'rev-parse', '--short=10', 'HEAD'],
+        cwd=str(REPO_ROOT), text=True, timeout=5
+    ).strip()
+except Exception:
+    COMMIT_HASH = 'unknown'
+
+DEPLOYED_AT = datetime.now(timezone.utc).isoformat()
+
+router = APIRouter(tags=['version'])
+
+
+@router.get('/api/version')
+def version():
+    return {'commit': COMMIT_HASH, 'deployed_at': DEPLOYED_AT}
+
+
+@router.get('/api/release-notes')
+def release_notes(since: str = '', limit: int = 5):
+    """Liefert Release-Notes seit der gegebenen Version.
+
+    'since' = letzte vom User gesehene Version. Liefert alle Eintraege NEUER
+    als diese Version. Ohne 'since' werden die letzten 'limit' Eintraege
+    geliefert.
+    """
+    if not RELEASES_FILE.exists():
+        return {'entries': [], 'current': COMMIT_HASH}
+    try:
+        with open(RELEASES_FILE, 'r', encoding='utf-8') as f:
+            data = json.load(f)
+    except Exception as e:
+        return {'entries': [], 'error': f'parse-failed: {e}'}
+
+    if since:
+        result = []
+        for entry in data:
+            if entry.get('version') == since:
+                break
+            result.append(entry)
+        return {'entries': result[:limit], 'current': COMMIT_HASH}
+
+    return {'entries': data[:limit], 'current': COMMIT_HASH}