chore: restructure project into backend and frontend folders

- Move all frontend code to frontend/ directory
- Add backend/ with Go project structure (cmd, internal, pkg)
- Add docker-compose.yml for orchestration

frontend/vite.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from 'vite'
+import react from '@vitejs/plugin-react'
+import tailwindcss from '@tailwindcss/vite'
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [react(), tailwindcss()],
+  server: {
+    allowedHosts: ['delivery.loca.lt', '.loca.lt'],
+    // hmr: {
+    //   host: 'delivery.loca.lt', // Use the hostname provided by localtunnel
+    //   port: 443, // Use HTTPS port
+    // },
+  },
+})