fix(pipeline): scan_sorties sync (was async, broke to_thread → coroutine instead of list → 500)

pipeline_runner/runner.py

@@ -121,7 +121,7 @@ async def run_pipeline(sortie_id: str, queue: asyncio.Queue) -> None:
     await _emit(queue, "write", 100, "Pipeline terminé")
 
 
-async def scan_sorties() -> list[dict]:
+def scan_sorties() -> list[dict]:
     """List available sorties on GDrive via rclone lsd (lent ~30s)."""
     result = subprocess.run(
         ["rclone", "lsd", GDRIVE_REMOTE],