Add React UI with Vite

Dashboard, agents, goals, issues, and projects pages with sidebar
navigation. API client layer, custom hooks, and shared layout
components. Built with Vite and TypeScript.

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

ui/src/api/client.ts

@@ -0,0 +1,22 @@
+const BASE = "/api";
+
+async function request<T>(path: string, init?: RequestInit): Promise<T> {
+  const res = await fetch(`${BASE}${path}`, {
+    headers: { "Content-Type": "application/json" },
+    ...init,
+  });
+  if (!res.ok) {
+    const body = await res.json().catch(() => null);
+    throw new Error(body?.error ?? `Request failed: ${res.status}`);
+  }
+  return res.json();
+}
+
+export const api = {
+  get: <T>(path: string) => request<T>(path),
+  post: <T>(path: string, body: unknown) =>
+    request<T>(path, { method: "POST", body: JSON.stringify(body) }),
+  patch: <T>(path: string, body: unknown) =>
+    request<T>(path, { method: "PATCH", body: JSON.stringify(body) }),
+  delete: <T>(path: string) => request<T>(path, { method: "DELETE" }),
+};