ZOD-341-Add unique constraint to user email and clean up duplicates

src/db/migrations/1761032305682-AddUniqueConstraintToUserEmail.ts

@@ -0,0 +1,26 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+export class AddUniqueConstraintToUserEmail1761032305682 implements MigrationInterface {
+    name = 'AddUniqueConstraintToUserEmail1761032305682'
+
+    public async up(queryRunner: QueryRunner): Promise<void> {
+        // Clean up duplicate emails - keep the oldest record (MIN id)
+        await queryRunner.query(`
+            DELETE FROM users
+            WHERE id IN (
+                SELECT u1.id
+                FROM users u1
+                INNER JOIN users u2 ON u1.email = u2.email AND u1.id > u2.id
+                WHERE u1.email IS NOT NULL
+            )
+        `);
+        
+        // Add unique constraint
+        await queryRunner.query(`ALTER TABLE "users" ADD CONSTRAINT "UQ_97672ac88f789774dd47f7c8be3" UNIQUE ("email")`);
+    }
+
+    public async down(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`ALTER TABLE "users" DROP CONSTRAINT "UQ_97672ac88f789774dd47f7c8be3"`);
+    }
+
+}