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/dom-helpers/esm/text.js

@@ -0,0 +1,36 @@
+var regExpNbspEntity = / /gi;
+var regExpNbspHex = /\xA0/g;
+var regExpSpaces = /\s+([^\s])/gm;
+/**
+ * Collects the text content of a given element.
+ * 
+ * @param node the element
+ * @param trim whether to remove trailing whitespace chars
+ * @param singleSpaces whether to convert multiple whitespace chars into a single space character
+ */
+
+export default function text(node, trim, singleSpaces) {
+  if (trim === void 0) {
+    trim = true;
+  }
+
+  if (singleSpaces === void 0) {
+    singleSpaces = true;
+  }
+
+  var elementText = '';
+
+  if (node) {
+    elementText = (node.textContent || '').replace(regExpNbspEntity, ' ').replace(regExpNbspHex, ' ');
+
+    if (trim) {
+      elementText = elementText.trim();
+    }
+
+    if (singleSpaces) {
+      elementText = elementText.replace(regExpSpaces, ' $1');
+    }
+  }
+
+  return elementText;
+}