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/subscript.js

@@ -0,0 +1,23 @@
+/**
+ * @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 Subscript = createLucideIcon("Subscript", [
+  ["path", { d: "m4 5 8 8", key: "1eunvl" }],
+  ["path", { d: "m12 5-8 8", key: "1ah0jp" }],
+  [
+    "path",
+    {
+      d: "M20 19h-4c0-1.5.44-2 1.5-2.5S20 15.33 20 14c0-.47-.17-.93-.48-1.29a2.11 2.11 0 0 0-2.62-.44c-.42.24-.74.62-.9 1.07",
+      key: "e8ta8j"
+    }
+  ]
+]);
+
+export { Subscript as default };
+//# sourceMappingURL=subscript.js.map