feat: migrate to Cloudflare Workers with icon and version upload

Replace Express/SQLite and web/ with frontend/, worker/, and wrangler deploy. Add optional app icon upload, date-based app_version, and build-app workflow input.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/App.tsx

@@ -0,0 +1,17 @@
+import { Route, Routes } from "react-router-dom";
+import Layout from "./components/Layout";
+import BuildList from "./pages/BuildList";
+import JobStatus from "./pages/JobStatus";
+import Upload from "./pages/Upload";
+
+export default function App() {
+  return (
+    <Routes>
+      <Route element={<Layout />}>
+        <Route path="/" element={<Upload />} />
+        <Route path="/jobs" element={<BuildList />} />
+        <Route path="/jobs/:id" element={<JobStatus />} />
+      </Route>
+    </Routes>
+  );
+}