fix(phase-0): resolve import paths and add backward compatibility test

- Fix TypeScript import paths to use relative imports instead of aliases
- Add comprehensive backward compatibility test script
- Verify existing functionality works correctly:
  * Legacy /api/track endpoint: ✅
  * /api/v1/track POST endpoint: ✅
  * /api/v1/track GET endpoint: ✅
- Ready for Docker testing of new TypeScript implementation

apps/api/package.json

@@ -17,7 +17,7 @@
     "cors": "^2.8.5",
     "cookie-parser": "^1.4.6",
     "express-rate-limit": "^7.1.5",
-    "rate-limiter-flexible": "^3.0.8",
+    "rate-limiter-flexible": "^5.0.3",
     "axios": "^1.6.7",
     "undici": "^6.2.1",
     "zod": "^3.22.4",