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/chart/PieChart.js

@@ -0,0 +1,32 @@
+/**
+ * @fileOverview Pie Chart
+ */
+import { generateCategoricalChart } from './generateCategoricalChart';
+import { PolarAngleAxis } from '../polar/PolarAngleAxis';
+import { PolarRadiusAxis } from '../polar/PolarRadiusAxis';
+import { formatAxisMap } from '../util/PolarUtils';
+import { Pie } from '../polar/Pie';
+export var PieChart = generateCategoricalChart({
+  chartName: 'PieChart',
+  GraphicalChild: Pie,
+  validateTooltipEventTypes: ['item'],
+  defaultTooltipEventType: 'item',
+  legendContent: 'children',
+  axisComponents: [{
+    axisType: 'angleAxis',
+    AxisComp: PolarAngleAxis
+  }, {
+    axisType: 'radiusAxis',
+    AxisComp: PolarRadiusAxis
+  }],
+  formatAxisMap: formatAxisMap,
+  defaultProps: {
+    layout: 'centric',
+    startAngle: 0,
+    endAngle: 360,
+    cx: '50%',
+    cy: '50%',
+    innerRadius: 0,
+    outerRadius: '80%'
+  }
+});