Reconcile schema with migrations and fix failed migration

- Align schema.prisma with add_15_features migration (15 discrepancies):
  nullability, column names, PKs, missing/extra columns, onDelete behavior
- Make universal_apply_programid migration idempotent for safe re-execution
- Add reconciliation migration for missing FKs and indexes
- Fix message.ts and mentor.ts to match corrected schema field names

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker/docker-entrypoint.sh

@@ -1,6 +1,9 @@
 #!/bin/sh
 set -e
 
+echo "==> Resolving any failed migrations..."
+npx prisma migrate resolve --rolled-back 20260207000000_universal_apply_programid 2>/dev/null || true
+
 echo "==> Running database migrations..."
 npx prisma migrate deploy