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/scale.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 Scale = createLucideIcon("Scale", [
+  ["path", { d: "m16 16 3-8 3 8c-.87.65-1.92 1-3 1s-2.13-.35-3-1Z", key: "7g6ntu" }],
+  ["path", { d: "m2 16 3-8 3 8c-.87.65-1.92 1-3 1s-2.13-.35-3-1Z", key: "ijws7r" }],
+  ["path", { d: "M7 21h10", key: "1b0cd5" }],
+  ["path", { d: "M12 3v18", key: "108xh3" }],
+  ["path", { d: "M3 7h2c2 0 5-1 7-2 2 1 5 2 7 2h2", key: "3gwbw2" }]
+]);
+
+export { Scale as default };
+//# sourceMappingURL=scale.js.map