add client: React + Vite + Capacitor prototype

Web app React 18 + TypeScript con quattro schermate: Setup (URL server +
password + test connessione), Ingredients (lista ingredienti e preferenze),
Recipes (lista 3 ricette generate), RecipeDetail (dettaglio e procedimento).
Persistenza URL/password via Capacitor Preferences. Pronto per build Android.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/capacitor.config.ts

@@ -0,0 +1,12 @@
+import type { CapacitorConfig } from '@capacitor/cli'
+
+const config: CapacitorConfig = {
+  appId: 'com.appetito.app',
+  appName: 'Appetito',
+  webDir: 'dist',
+  android: {
+    allowMixedContent: true,
+  },
+}
+
+export default config