fix: update db.ts to refresh cached Prisma client for Prompt model

lib/db.ts

@@ -15,8 +15,12 @@ const globalForPrisma = globalThis as unknown as {
 
 function getPrismaClient(): PrismaClient {
   if (process.env.NODE_ENV !== 'production' && globalForPrisma.prisma) {
-    // Check if newly added models (e.g. category) exist on cached client
-    if ((globalForPrisma.prisma as any).category) {
+    // Ensure all models (category, cheatsheet, prompt) exist on cached client
+    if (
+      (globalForPrisma.prisma as any).category &&
+      (globalForPrisma.prisma as any).cheatsheet &&
+      (globalForPrisma.prisma as any).prompt
+    ) {
       return globalForPrisma.prisma;
     }
   }