feat(api): add user flagging functionality

prisma/migrations/20251222132600_add_user_flagged_and_unusual_activity/migration.sql

@@ -0,0 +1,7 @@
+-- AlterEnum
+ALTER TYPE "DelistReason" ADD VALUE 'UNUSUAL_ACTIVITY';
+
+-- AlterTable
+ALTER TABLE "users" ADD COLUMN "flagged" BOOLEAN NOT NULL DEFAULT false;
+ALTER TABLE "users" ADD COLUMN "flaggedAt" TIMESTAMP(3);
+ALTER TABLE "users" ADD COLUMN "flaggedReason" TEXT;

prisma/schema.prisma

@@ -23,6 +23,9 @@ model User {
   githubUsername            String?
   apiKey                    String?                @unique
   mcpPromptsPublicByDefault Boolean                @default(false)
+  flagged                   Boolean                @default(false)
+  flaggedAt                 DateTime?
+  flaggedReason             String?
   accounts                  Account[]
   subscriptions  CategorySubscription[]
   changeRequests ChangeRequest[]
@@ -408,4 +411,5 @@ enum DelistReason {
   LOW_QUALITY
   NOT_LLM_INSTRUCTION
   MANUAL
+  UNUSUAL_ACTIVITY
 }