feat: add dynamic base URL configuration using environment variables (#1511)

- Replace hardcoded base URL in HttpClient.ts with environment variable support
- Add NEXT_PUBLIC_API_BASE_URL environment variable for dynamic configuration
- Add dev:local script for development with localhost:5300 backend
- Development: uses localhost:5300, Production: uses / (relative path)
- Eliminates need for manual code changes when switching environments

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Junyan Qin <Chin>, 秦骏言 in Chinese, you can call me my english name Rock Chin. <rockchinq@gmail.com>

web/package.json

@@ -4,6 +4,7 @@
   "private": true,
   "scripts": {
     "dev": "next dev --turbopack",
+    "dev:local": "NEXT_PUBLIC_API_BASE_URL=http://localhost:5300 next dev --turbopack",
     "build": "next build",
     "start": "next start",
     "lint": "next lint",