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>

src/server/routers/message.ts

@@ -247,7 +247,7 @@ export const messageRouter = router({
           subject: input.subject,
           body: input.body,
           variables: input.variables ?? undefined,
-          createdById: ctx.user.id,
+          createdBy: ctx.user.id,
         },
       })