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/lodash/upperCase.js

@@ -0,0 +1,27 @@
+var createCompounder = require('./_createCompounder');
+
+/**
+ * Converts `string`, as space separated words, to upper case.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category String
+ * @param {string} [string=''] The string to convert.
+ * @returns {string} Returns the upper cased string.
+ * @example
+ *
+ * _.upperCase('--foo-bar');
+ * // => 'FOO BAR'
+ *
+ * _.upperCase('fooBar');
+ * // => 'FOO BAR'
+ *
+ * _.upperCase('__foo_bar__');
+ * // => 'FOO BAR'
+ */
+var upperCase = createCompounder(function(result, word, index) {
+  return result + (index ? ' ' : '') + word.toUpperCase();
+});
+
+module.exports = upperCase;