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/folder-open-dot.js

@@ -0,0 +1,22 @@
+/**
+ * @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 FolderOpenDot = createLucideIcon("FolderOpenDot", [
+  [
+    "path",
+    {
+      d: "m6 14 1.45-2.9A2 2 0 0 1 9.24 10H20a2 2 0 0 1 1.94 2.5l-1.55 6a2 2 0 0 1-1.94 1.5H4a2 2 0 0 1-2-2V5c0-1.1.9-2 2-2h3.93a2 2 0 0 1 1.66.9l.82 1.2a2 2 0 0 0 1.66.9H18a2 2 0 0 1 2 2v2",
+      key: "1nmvlm"
+    }
+  ],
+  ["circle", { cx: "14", cy: "15", r: "1", key: "1gm4qj" }]
+]);
+
+export { FolderOpenDot as default };
+//# sourceMappingURL=folder-open-dot.js.map