Fix clear-data missing username arg for discard_run

The discard_run service method requires username as the third argument.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/routers/home.py

@@ -94,6 +94,7 @@ async def clear_user_data(request: Request):
     from ..dependencies import get_redis_client, get_cache_manager
 
     actor_id = user.actor_id
+    username = user.username
     deleted = {
         "runs": 0,
         "recipes": 0,
@@ -108,7 +109,7 @@ async def clear_user_data(request: Request):
         runs = await run_service.list_runs(actor_id, offset=0, limit=10000)
         for run in runs:
             try:
-                await run_service.discard_run(run["run_id"], actor_id)
+                await run_service.discard_run(run["run_id"], actor_id, username)
                 deleted["runs"] += 1
             except Exception as e:
                 errors.append(f"Run {run['run_id']}: {e}")