fix(iter-v2): T01 QA fixes - race condition, hook regex, deleted user check

- BUG-1: Pre-commit hook allows .env.example (grep -v filter)
- BUG-2: /auth/refresh uses transaction + FOR UPDATE to prevent race condition
- WARN-1: Auth middleware checks deleted_at with 5-min TTL cache
- WARN-2: PUT /admin/users/:id/status filters deleted_at IS NULL
- WARN-3: Install node-cron@^3.0.3

server/package.json

@@ -15,7 +15,8 @@
     "express": "^4.18.2",
     "express-rate-limit": "^8.5.2",
     "multer": "^2.1.1",
-    "mysql2": "^3.9.0"
+    "mysql2": "^3.9.0",
+    "node-cron": "^3.0.3"
   },
   "devDependencies": {
     "@types/cors": "^2.8.17",