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/camelCase.js

@@ -0,0 +1,29 @@
+var capitalize = require('./capitalize'),
+    createCompounder = require('./_createCompounder');
+
+/**
+ * Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category String
+ * @param {string} [string=''] The string to convert.
+ * @returns {string} Returns the camel cased string.
+ * @example
+ *
+ * _.camelCase('Foo Bar');
+ * // => 'fooBar'
+ *
+ * _.camelCase('--foo-bar--');
+ * // => 'fooBar'
+ *
+ * _.camelCase('__FOO_BAR__');
+ * // => 'fooBar'
+ */
+var camelCase = createCompounder(function(result, word, index) {
+  word = word.toLowerCase();
+  return result + (index ? capitalize(word) : word);
+});
+
+module.exports = camelCase;