Fix Windows IPv6 issue: use 127.0.0.1 instead of localhost in Vite proxy

On Windows, 'localhost' can resolve to IPv6 ::1 instead of IPv4
127.0.0.1, causing ECONNREFUSED when the Vite dev proxy tries to
reach the Express server. Using explicit 127.0.0.1 avoids this.

Fixes #12

vite.config.ts

@@ -10,19 +10,19 @@ export default defineConfig(({ mode }) => {
       host: '0.0.0.0',
       proxy: {
         '/api': {
-          target: 'http://localhost:3001',
+          target: 'http://127.0.0.1:3001',
           changeOrigin: true,
         },
         '/audio': {
-          target: 'http://localhost:3001',
+          target: 'http://127.0.0.1:3001',
           changeOrigin: true,
         },
         '/editor': {
-          target: 'http://localhost:3001',
+          target: 'http://127.0.0.1:3001',
           changeOrigin: true,
         },
         '/blog': {
-          target: 'http://localhost:3001',
+          target: 'http://127.0.0.1:3001',
           changeOrigin: true,
         },
       },