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/matches.js

@@ -0,0 +1,92 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.fuzzyMatches = fuzzyMatches;
+exports.getDefaultNormalizer = getDefaultNormalizer;
+exports.makeNormalizer = makeNormalizer;
+exports.matches = matches;
+function assertNotNullOrUndefined(matcher) {
+  if (matcher === null || matcher === undefined) {
+    throw new Error(
+    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions -- implicitly converting `T` to `string`
+    `It looks like ${matcher} was passed instead of a matcher. Did you do something like getByText(${matcher})?`);
+  }
+}
+function fuzzyMatches(textToMatch, node, matcher, normalizer) {
+  if (typeof textToMatch !== 'string') {
+    return false;
+  }
+  assertNotNullOrUndefined(matcher);
+  const normalizedText = normalizer(textToMatch);
+  if (typeof matcher === 'string' || typeof matcher === 'number') {
+    return normalizedText.toLowerCase().includes(matcher.toString().toLowerCase());
+  } else if (typeof matcher === 'function') {
+    return matcher(normalizedText, node);
+  } else {
+    return matchRegExp(matcher, normalizedText);
+  }
+}
+function matches(textToMatch, node, matcher, normalizer) {
+  if (typeof textToMatch !== 'string') {
+    return false;
+  }
+  assertNotNullOrUndefined(matcher);
+  const normalizedText = normalizer(textToMatch);
+  if (matcher instanceof Function) {
+    return matcher(normalizedText, node);
+  } else if (matcher instanceof RegExp) {
+    return matchRegExp(matcher, normalizedText);
+  } else {
+    return normalizedText === String(matcher);
+  }
+}
+function getDefaultNormalizer({
+  trim = true,
+  collapseWhitespace = true
+} = {}) {
+  return text => {
+    let normalizedText = text;
+    normalizedText = trim ? normalizedText.trim() : normalizedText;
+    normalizedText = collapseWhitespace ? normalizedText.replace(/\s+/g, ' ') : normalizedText;
+    return normalizedText;
+  };
+}
+
+/**
+ * Constructs a normalizer to pass to functions in matches.js
+ * @param {boolean|undefined} trim The user-specified value for `trim`, without
+ * any defaulting having been applied
+ * @param {boolean|undefined} collapseWhitespace The user-specified value for
+ * `collapseWhitespace`, without any defaulting having been applied
+ * @param {Function|undefined} normalizer The user-specified normalizer
+ * @returns {Function} A normalizer
+ */
+
+function makeNormalizer({
+  trim,
+  collapseWhitespace,
+  normalizer
+}) {
+  if (!normalizer) {
+    // No custom normalizer specified. Just use default.
+    return getDefaultNormalizer({
+      trim,
+      collapseWhitespace
+    });
+  }
+  if (typeof trim !== 'undefined' || typeof collapseWhitespace !== 'undefined') {
+    // They've also specified a value for trim or collapseWhitespace
+    throw new Error('trim and collapseWhitespace are not supported with a normalizer. ' + 'If you want to use the default trim and collapseWhitespace logic in your normalizer, ' + 'use "getDefaultNormalizer({trim, collapseWhitespace})" and compose that into your normalizer');
+  }
+  return normalizer;
+}
+function matchRegExp(matcher, text) {
+  const match = matcher.test(text);
+  if (matcher.global && matcher.lastIndex !== 0) {
+    console.warn(`To match all elements we had to reset the lastIndex of the RegExp because the global flag is enabled. We encourage to remove the global flag from the RegExp.`);
+    matcher.lastIndex = 0;
+  }
+  return match;
+}