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/@testing-library/dom/dist/queries/test-id.js

@@ -0,0 +1,23 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.queryByTestId = exports.queryAllByTestId = exports.getByTestId = exports.getAllByTestId = exports.findByTestId = exports.findAllByTestId = void 0;
+var _helpers = require("../helpers");
+var _queryHelpers = require("../query-helpers");
+var _allUtils = require("./all-utils");
+const getTestIdAttribute = () => (0, _allUtils.getConfig)().testIdAttribute;
+const queryAllByTestId = (...args) => {
+  (0, _helpers.checkContainerType)(args[0]);
+  return (0, _allUtils.queryAllByAttribute)(getTestIdAttribute(), ...args);
+};
+const getMultipleError = (c, id) => `Found multiple elements by: [${getTestIdAttribute()}="${id}"]`;
+const getMissingError = (c, id) => `Unable to find an element by: [${getTestIdAttribute()}="${id}"]`;
+const queryAllByTestIdWithSuggestions = exports.queryAllByTestId = (0, _queryHelpers.wrapAllByQueryWithSuggestion)(queryAllByTestId, queryAllByTestId.name, 'queryAll');
+const [queryByTestId, getAllByTestId, getByTestId, findAllByTestId, findByTestId] = (0, _allUtils.buildQueries)(queryAllByTestId, getMultipleError, getMissingError);
+exports.findByTestId = findByTestId;
+exports.findAllByTestId = findAllByTestId;
+exports.getByTestId = getByTestId;
+exports.getAllByTestId = getAllByTestId;
+exports.queryByTestId = queryByTestId;