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/sucrase/dist/transformers/Transformer.js

@@ -0,0 +1,16 @@
+"use strict";Object.defineProperty(exports, "__esModule", {value: true}); class Transformer {
+  // Return true if anything was processed, false otherwise.
+  
+
+  getPrefixCode() {
+    return "";
+  }
+
+  getHoistedCode() {
+    return "";
+  }
+
+  getSuffixCode() {
+    return "";
+  }
+} exports.default = Transformer;