fix: remove Vercel cron entries — crons run via Supabase pg_cron

All cron jobs are triggered by Supabase pg_cron + pg_net calling
the HTTP endpoints directly. Removes vercel.json cron config to
avoid confusion and potential double-triggering.

Co-authored-by: content <content@miriad.systems>

Author: content

vercel.json

@@ -1,21 +1,3 @@
 {
-	"$schema": "https://openapi.vercel.sh/vercel.json",
-	"crons": [
-		{
-			"path": "/api/cron",
-			"schedule": "0 0 * * *"
-		},
-		{
-			"path": "/api/cron/ingest",
-			"schedule": "0 6 * * *"
-		},
-		{
-			"path": "/api/cron/sponsor-outreach",
-			"schedule": "0 9 * * 1,4"
-		},
-		{
-			"path": "/api/cron/check-renders",
-			"schedule": "0 7 * * *"
-		}
-	]
+	"$schema": "https://openapi.vercel.sh/vercel.json"
 }