feat(api): add delist reasons and quality check functionality

prisma/migrations/20251217173000_add_delist_reason/migration.sql

@@ -0,0 +1,5 @@
+-- CreateEnum
+CREATE TYPE "DelistReason" AS ENUM ('TOO_SHORT', 'NOT_ENGLISH', 'LOW_QUALITY', 'NOT_LLM_INSTRUCTION', 'MANUAL');
+
+-- AlterTable
+ALTER TABLE "prompts" ADD COLUMN "delistReason" "DelistReason";

prisma/schema.prisma

@@ -98,6 +98,7 @@ model Prompt {
   isFeatured          Boolean            @default(false)
   isUnlisted          Boolean            @default(false)
   unlistedAt          DateTime?
+  delistReason        DelistReason?
   deletedAt           DateTime?
   changeRequests      ChangeRequest[]
   pinnedBy            PinnedPrompt[]
@@ -314,3 +315,11 @@ enum WebhookEvent {
   PROMPT_UPDATED
   PROMPT_DELETED
 }
+
+enum DelistReason {
+  TOO_SHORT
+  NOT_ENGLISH
+  LOW_QUALITY
+  NOT_LLM_INSTRUCTION
+  MANUAL
+}