Add remove rating feature

Bouton ✕ sur les films notés 10/10 pour supprimer la note via DELETE /api/rate/:id.

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

main.py

@@ -187,4 +187,16 @@ async def rate_movie(request: Request, trakt_id: int, body: RateBody):
     return {"success": True}
 
 
+@app.delete("/api/rate/{trakt_id}")
+async def remove_rating(request: Request, trakt_id: int):
+    token = request.session.get("access_token")
+    if not token:
+        raise HTTPException(401, "Not authenticated")
+
+    trakt = TraktClient(TRAKT_CLIENT_ID, token)
+    await trakt.remove_rating(trakt_id)
+    cache_del(f"movies_{token[:16]}")
+    return {"success": True}
+
+
 app.mount("/static", StaticFiles(directory="static"), name="static")