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/app/providers.tsx

@@ -2,6 +2,7 @@
 
 import { useState } from 'react'
 import { SessionProvider } from 'next-auth/react'
+import { ThemeProvider } from 'next-themes'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { httpBatchLink } from '@trpc/client'
 import superjson from 'superjson'
@@ -52,10 +53,12 @@ export function Providers({ children }: { children: React.ReactNode }) {
   )
 
   return (
-    <SessionProvider>
-      <trpc.Provider client={trpcClient} queryClient={queryClient}>
-        <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
-      </trpc.Provider>
-    </SessionProvider>
+    <ThemeProvider attribute="class" defaultTheme="light" enableSystem={false}>
+      <SessionProvider>
+        <trpc.Provider client={trpcClient} queryClient={queryClient}>
+          <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+        </trpc.Provider>
+      </SessionProvider>
+    </ThemeProvider>
   )
 }