fix(tenants): cast Prisma unique error for TS narrowing

Co-authored-by: Cursor <cursoragent@cursor.com>

src/tenants/tenants.service.ts

@@ -437,7 +437,7 @@ export class TenantsService {
     if (!(error instanceof Prisma.PrismaClientKnownRequestError)) {
       return;
     }
-    const prismaError = error;
+    const prismaError = error as Prisma.PrismaClientKnownRequestError;
     if (prismaError.code !== 'P2002') {
       return;
     }