chore(frontend): scaffold Vite React TypeScript application

frontend-s2s/config/backend-proxy.ts

@@ -0,0 +1,16 @@
+import type { ProxyOptions } from "vite";
+
+/** Preserve the public origin used by FastAPI to construct the speech WebSocket URL. */
+export function createBackendProxy(target: string): Record<string, ProxyOptions> {
+  const http: ProxyOptions = { target, changeOrigin: false };
+  return {
+    "/api": http,
+    "/v1/realtime": { ...http, ws: true },
+    "/docs": http,
+    "/redoc": http,
+    "/openapi.json": http,
+    "/oauth": http,
+    "/project": http,
+    "/public/docs.html": http,
+  };
+}