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/autoprefixer/lib/hacks/grid-start.js

@@ -0,0 +1,33 @@
+let Declaration = require('../declaration')
+
+class GridStart extends Declaration {
+  /**
+   * Do not add prefix for unsupported value in IE
+   */
+  check(decl) {
+    let value = decl.value
+    return !value.includes('/') && !value.includes('span')
+  }
+
+  /**
+   * Return a final spec property
+   */
+  normalize(prop) {
+    return prop.replace('-start', '')
+  }
+
+  /**
+   * Change property name for IE
+   */
+  prefixed(prop, prefix) {
+    let result = super.prefixed(prop, prefix)
+    if (prefix === '-ms-') {
+      result = result.replace('-start', '')
+    }
+    return result
+  }
+}
+
+GridStart.names = ['grid-row-start', 'grid-column-start']
+
+module.exports = GridStart