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/loupe/lib/class.js

@@ -0,0 +1,18 @@
+import getFuncName from 'get-func-name'
+import inspectObject from './object'
+
+const toStringTag = typeof Symbol !== 'undefined' && Symbol.toStringTag ? Symbol.toStringTag : false
+
+export default function inspectClass(value, options) {
+  let name = ''
+  if (toStringTag && toStringTag in value) {
+    name = value[toStringTag]
+  }
+  name = name || getFuncName(value.constructor)
+  // Babel transforms anonymous classes to the name `_class`
+  if (!name || name === '_class') {
+    name = '<Anonymous Class>'
+  }
+  options.truncate -= name.length
+  return `${name}${inspectObject(value, options)}`
+}