refactor(api): remove AI worker, add ai api route, add usage tiers

- Remove separate AI worker service
- Added generation limits:
  FREE: 1000/month (For the beta version)
  PRO: 500/month
  ENTERPRISE: 1000/month
- Integrate AI functionality into main API routes
- Added monthly generations reset and usage tier upgrade API routes
- Upgrade tier page to be added along with profile page section

frontend/package.json

@@ -9,6 +9,7 @@
     "lint": "next lint"
   },
   "dependencies": {
+    "@anthropic-ai/sdk": "^0.32.1",
     "@atlaskit/pragmatic-drag-and-drop": "^1.1.7",
     "@clerk/nextjs": "^4.29.12",
     "@clerk/themes": "^1.7.12",