feat(frontend): add API client, layout, and routing

- Create Axios-based API client with sources, jobs, and dashboard endpoints
- Add responsive Layout component with navigation sidebar
- Set up React Router with Dashboard, Backups, and Settings routes
- Configure TanStack Query provider with default options
- Use lucide-react for navigation icons

frontend/node_modules/react-dom/server.browser.js

@@ -0,0 +1,17 @@
+'use strict';
+
+var l, s;
+if (process.env.NODE_ENV === 'production') {
+  l = require('./cjs/react-dom-server-legacy.browser.production.min.js');
+  s = require('./cjs/react-dom-server.browser.production.min.js');
+} else {
+  l = require('./cjs/react-dom-server-legacy.browser.development.js');
+  s = require('./cjs/react-dom-server.browser.development.js');
+}
+
+exports.version = l.version;
+exports.renderToString = l.renderToString;
+exports.renderToStaticMarkup = l.renderToStaticMarkup;
+exports.renderToNodeStream = l.renderToNodeStream;
+exports.renderToStaticNodeStream = l.renderToStaticNodeStream;
+exports.renderToReadableStream = s.renderToReadableStream;