Add staging environment documentation and minor fixes

- Document staging vs production DB separation (autonet_staging)
- Add staging sync and deployment commands to CLAUDE.md
- Update changelog with 2025-01-03 changes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/package.json

@@ -6,7 +6,9 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start -p 3000",
-    "lint": "next lint"
+    "lint": "next lint",
+    "audit": "npm audit --omit=dev",
+    "audit:fix": "npm audit fix --omit=dev"
   },
   "dependencies": {
     "@heroicons/react": "^2.1.1",