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/scissors-square.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 ScissorsSquare = createLucideIcon("ScissorsSquare", [
+  ["rect", { width: "20", height: "20", x: "2", y: "2", rx: "2", key: "1btzen" }],
+  ["circle", { cx: "8", cy: "8", r: "2", key: "14cg06" }],
+  ["path", { d: "M9.414 9.414 12 12", key: "qz4lzr" }],
+  ["path", { d: "M14.8 14.8 18 18", key: "11flf1" }],
+  ["circle", { cx: "8", cy: "16", r: "2", key: "1acxsx" }],
+  ["path", { d: "m18 6-8.586 8.586", key: "11kzk1" }]
+]);
+
+export { ScissorsSquare as default };
+//# sourceMappingURL=scissors-square.js.map