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/index.ts

@@ -0,0 +1,5 @@
+export { api } from "./client";
+export { agentsApi } from "./agents";
+export { projectsApi } from "./projects";
+export { issuesApi } from "./issues";
+export { goalsApi } from "./goals";