feat: make API URL configurable and improve code quality

- Add configurable API URL support via environment variables
- Update nginx configuration with environment variable substitution
- Create nginx template for dynamic proxy configuration
- Update Docker configuration for environment variable handling
- Fix hardcoded localhost:8000 references in error messages
- Add proper TypeScript types for health check API
- Format all code with Prettier for consistency
- Update documentation with configuration instructions
- Improve error messages to be environment-agnostic
- Fix duplicate imports and type safety issues

BREAKING: API URL is now configurable via VITE_API_URL (dev) and API_BACKEND_URL (prod)

frontend/tailwind.config.js

@@ -1,13 +1,8 @@
 /** @type {import('tailwindcss').Config} */
 export default {
-  content: [
-    "./index.html",
-    "./src/**/*.{js,ts,jsx,tsx}",
-  ],
+  content: ["./index.html", "./src/**/*.{js,ts,jsx,tsx}"],
   theme: {
     extend: {},
   },
-  plugins: [
-    require('@tailwindcss/forms'),
-  ],
+  plugins: [require("@tailwindcss/forms")],
 };