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/message-square-dashed.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 MessageSquareDashed = createLucideIcon("MessageSquareDashed", [
+  ["path", { d: "M3 6V5c0-1.1.9-2 2-2h2", key: "9usibi" }],
+  ["path", { d: "M11 3h3", key: "1c3ji7" }],
+  ["path", { d: "M18 3h1c1.1 0 2 .9 2 2", key: "19esxn" }],
+  ["path", { d: "M21 9v2", key: "p14lih" }],
+  ["path", { d: "M21 15c0 1.1-.9 2-2 2h-1", key: "1fo1j8" }],
+  ["path", { d: "M14 17h-3", key: "1w4p2m" }],
+  ["path", { d: "m7 17-4 4v-5", key: "ph9x1h" }],
+  ["path", { d: "M3 12v-2", key: "856n1q" }]
+]);
+
+export { MessageSquareDashed as default };
+//# sourceMappingURL=message-square-dashed.js.map