refactor: organize frontend by feature

Move the React application into app, api, feature, component, style, and type boundaries, and rebuild the interview scheduler with a responsive details-and-team layout.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/README.md

@@ -18,9 +18,21 @@ npm run build
 Run one test:
 
 ```bash
-npm test -- src/App.test.tsx -t "shows answer inputs"
+npm test -- src/app/App.test.tsx -t "filters jobs by title"
 ```
 
+## Source structure
+
+- `src/app` contains the application shell, providers, routes, and route-level tests.
+- `src/features` groups pages and components by business capability.
+- `src/components` contains UI shared by multiple features.
+- `src/api/client.ts` is the typed HTTP boundary.
+- `src/types` contains API and domain types.
+- `src/styles/global.css` contains shared tokens and layout styles.
+
+Keep feature-only UI close to its feature instead of adding more screens to the
+application shell.
+
 ## API integration
 
 Vite proxies `/api` to `http://localhost:8080`. Login stores the returned JWT in