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/microscope.js

@@ -0,0 +1,20 @@
+/**
+ * @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 Microscope = createLucideIcon("Microscope", [
+  ["path", { d: "M6 18h8", key: "1borvv" }],
+  ["path", { d: "M3 22h18", key: "8prr45" }],
+  ["path", { d: "M14 22a7 7 0 1 0 0-14h-1", key: "1jwaiy" }],
+  ["path", { d: "M9 14h2", key: "197e7h" }],
+  ["path", { d: "M9 12a2 2 0 0 1-2-2V6h6v4a2 2 0 0 1-2 2Z", key: "1bmzmy" }],
+  ["path", { d: "M12 6V3a1 1 0 0 0-1-1H9a1 1 0 0 0-1 1v3", key: "1drr47" }]
+]);
+
+export { Microscope as default };
+//# sourceMappingURL=microscope.js.map