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/escalade/dist/index.js

@@ -0,0 +1,22 @@
+const { dirname, resolve } = require('path');
+const { readdir, stat } = require('fs');
+const { promisify } = require('util');
+
+const toStats = promisify(stat);
+const toRead = promisify(readdir);
+
+module.exports = async function (start, callback) {
+	let dir = resolve('.', start);
+	let tmp, stats = await toStats(dir);
+
+	if (!stats.isDirectory()) {
+		dir = dirname(dir);
+	}
+
+	while (true) {
+		tmp = await callback(dir, await toRead(dir));
+		if (tmp) return resolve(dir, tmp);
+		dir = dirname(tmp = dir);
+		if (tmp === dir) break;
+	}
+}