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/display-value.js

@@ -0,0 +1,40 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.queryByDisplayValue = exports.queryAllByDisplayValue = exports.getByDisplayValue = exports.getAllByDisplayValue = exports.findByDisplayValue = exports.findAllByDisplayValue = void 0;
+var _queryHelpers = require("../query-helpers");
+var _helpers = require("../helpers");
+var _allUtils = require("./all-utils");
+const queryAllByDisplayValue = (container, value, {
+  exact = true,
+  collapseWhitespace,
+  trim,
+  normalizer
+} = {}) => {
+  (0, _helpers.checkContainerType)(container);
+  const matcher = exact ? _allUtils.matches : _allUtils.fuzzyMatches;
+  const matchNormalizer = (0, _allUtils.makeNormalizer)({
+    collapseWhitespace,
+    trim,
+    normalizer
+  });
+  return Array.from(container.querySelectorAll(`input,textarea,select`)).filter(node => {
+    if (node.tagName === 'SELECT') {
+      const selectedOptions = Array.from(node.options).filter(option => option.selected);
+      return selectedOptions.some(optionNode => matcher((0, _allUtils.getNodeText)(optionNode), optionNode, value, matchNormalizer));
+    } else {
+      return matcher(node.value, node, value, matchNormalizer);
+    }
+  });
+};
+const getMultipleError = (c, value) => `Found multiple elements with the display value: ${value}.`;
+const getMissingError = (c, value) => `Unable to find an element with the display value: ${value}.`;
+const queryAllByDisplayValueWithSuggestions = exports.queryAllByDisplayValue = (0, _queryHelpers.wrapAllByQueryWithSuggestion)(queryAllByDisplayValue, queryAllByDisplayValue.name, 'queryAll');
+const [queryByDisplayValue, getAllByDisplayValue, getByDisplayValue, findAllByDisplayValue, findByDisplayValue] = (0, _allUtils.buildQueries)(queryAllByDisplayValue, getMultipleError, getMissingError);
+exports.findByDisplayValue = findByDisplayValue;
+exports.findAllByDisplayValue = findAllByDisplayValue;
+exports.getByDisplayValue = getByDisplayValue;
+exports.getAllByDisplayValue = getAllByDisplayValue;
+exports.queryByDisplayValue = queryByDisplayValue;