chore(webapp): prevent db:seed script hang (#3962)

Currently the `db:seed` script just hangs on success.

This PR adds `process.exit(0)` to the finally block after db disconnect
so the script exits properly.

---------

Co-authored-by: Chris Arderne <chris@trigger.dev>

.server-changes/prevent-db-seed-script-hang.md

@@ -0,0 +1,6 @@
+---
+area: webapp
+type: fix
+---
+
+Exit db:seed script on success to prevent hanging.

apps/webapp/seed.mts

@@ -168,6 +168,7 @@ seed()
   })
   .finally(async () => {
     await prisma.$disconnect();
+    process.exit(0);
   });
 
 async function findOrCreateOrganization(