fix: change check-renders cron to daily (Hobby plan limit)

Hobby plan only supports daily cron jobs. Changed from hourly (0 * * * *)
to daily at 7am UTC (0 7 * * *). Use manual curl for on-demand checks.

Author: Miriad

vercel.json

@@ -15,7 +15,7 @@
 		},
 		{
 			"path": "/api/cron/check-renders",
-			"schedule": "0 * * * *"
+			"schedule": "0 7 * * *"
 		}
 	]
 }