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/lucide-react/dist/esm/icons/file-digit.js

@@ -0,0 +1,19 @@
+/**
+ * @license lucide-react v0.303.0 - ISC
+ *
+ * This source code is licensed under the ISC license.
+ * See the LICENSE file in the root directory of this source tree.
+ */
+
+import createLucideIcon from '../createLucideIcon.js';
+
+const FileDigit = createLucideIcon("FileDigit", [
+  ["rect", { width: "4", height: "6", x: "2", y: "12", rx: "2", key: "jm304g" }],
+  ["path", { d: "M14 2v6h6", key: "1kof46" }],
+  ["path", { d: "M4 22h14a2 2 0 0 0 2-2V7.5L14.5 2H6a2 2 0 0 0-2 2v4", key: "702lig" }],
+  ["path", { d: "M10 12h2v6", key: "12zw74" }],
+  ["path", { d: "M10 18h4", key: "1ulq68" }]
+]);
+
+export { FileDigit as default };
+//# sourceMappingURL=file-digit.js.map