refactor: Remove /ui path prefix

Removed the /ui basePath from Next.js configuration to serve the app at root path:

- Removed basePath: "/ui" from next.config.ts
- Updated all API route calls from /ui/api/* to /api/*
- App now accessible at root path instead of /ui subdirectory

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

next.config.ts

@@ -1,7 +1,6 @@
 import type { NextConfig } from "next";
 
 const nextConfig: NextConfig = {
-  basePath: "/ui",
   output: "standalone",
   experimental: {
     optimizePackageImports: ["lucide-react"],