Security Nice-to-Have: Dockerfile, Magic-Bytes, Path-Traversal, TABLE_MAP, Deps

- Dockerfile: non-root user appuser, chown /data + /app
- media_utils: validate_upload() Magic-Byte-Check (JPEG/PNG/GIF/WebP/MP4/WebM)
- media_utils: safe_media_path() Path-Traversal-Schutz beim Löschen
- diary/health/dogs: safe_media_path() statt os.path.join + lstrip
- diary: validate_upload() vor jedem Medien-Upload
- forum: _LIKE_TABLE dict statt dynamischer String-Interpolation
- requirements: uvicorn 0.34, PyJWT 2.10.1, pydantic 2.10.6, bcrypt 4.3, httpx 0.28.1, anthropic 0.49
- SW by-v319, APP_VER 307

backend/routes/health.py

@@ -7,6 +7,7 @@ from pydantic import BaseModel
 from typing import Optional
 from database import db
 from auth import get_current_user
+from media_utils import safe_media_path
 
 router    = APIRouter()
 MEDIA_DIR = os.getenv("MEDIA_DIR", "/data/media")
@@ -219,10 +220,8 @@ async def delete_dokument(dog_id: int, entry_id: int, user=Depends(get_current_u
 
         datei_url = entry["datei_url"]
         if datei_url:
-            # datei_url z.B. "/media/health/health_42_abc12345.pdf"
-            filename = datei_url.lstrip("/media/")
-            path = os.path.join(MEDIA_DIR, filename)
-            if os.path.isfile(path):
+            path = safe_media_path(MEDIA_DIR, datei_url)
+            if path and os.path.isfile(path):
                 os.remove(path)
 
         conn.execute(
@@ -338,9 +337,10 @@ async def delete_media_item(dog_id: int, entry_id: int, media_id: int,
         ).fetchone()
         if not row:
             raise HTTPException(404, "Medium nicht gefunden.")
-        file_path = os.path.join(MEDIA_DIR, row["url"].lstrip("/media/"))
-        try: os.remove(file_path)
-        except OSError: pass
+        file_path = safe_media_path(MEDIA_DIR, row["url"])
+        if file_path:
+            try: os.remove(file_path)
+            except OSError: pass
         conn.execute("DELETE FROM health_media WHERE id=?", (media_id,))