vite: bind the dev server to 127.0.0.1, where the app's WebView looks

Vite 6 on modern Node binds [::1] alone when no host is set, while WebView2
resolves the devUrl's "localhost" to IPv4 — the window opens on
ERR_CONNECTION_REFUSED while curl and every browser say the server is fine.

vite.config.js

@@ -7,6 +7,11 @@ export default defineConfig({
     server: {
         port: 1421,
         strictPort: true,
+        // Bind IPv4 loopback explicitly. With no host, Vite on modern Node
+        // binds [::1] ONLY, while WebView2 resolves the devUrl's "localhost"
+        // to 127.0.0.1 — so the window opens on ERR_CONNECTION_REFUSED while
+        // curl and the browser (which try ::1) both say the server is fine.
+        host: "127.0.0.1",
         watch: {
             // Never watch the Rust build dir: cargo locks files mid-compile,
             // which crashes Vite's watcher (EBUSY) and kills tauri dev.