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/recharts/es6/util/calculateViewBox.js

@@ -0,0 +1,18 @@
+import memoize from 'lodash/memoize';
+/**
+ * This is memoized because the viewBox is unlikely to change often
+ * - but because it is computed from offset, any change to it would re-render all children.
+ *
+ * And because we have many readers of the viewBox, and update it only rarely,
+ * then let's optimize with memoization.
+ */
+export var calculateViewBox = memoize(function (offset) {
+  return {
+    x: offset.left,
+    y: offset.top,
+    width: offset.width,
+    height: offset.height
+  };
+}, function (offset) {
+  return ['l', offset.left, 't', offset.top, 'w', offset.width, 'h', offset.height].join('');
+});