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/cssstyle/lib/properties/width.js

@@ -0,0 +1,31 @@
+"use strict";
+
+const parsers = require("../parsers");
+
+module.exports.parse = function parse(v) {
+  const dim = parsers.parseMeasurement(v, true);
+  if (dim) {
+    return dim;
+  }
+  const keywords = ["auto", "min-content", "max-content", "fit-content"];
+  return parsers.parseKeyword(v, keywords);
+};
+
+module.exports.isValid = function isValid(v) {
+  if (v === "") {
+    return true;
+  }
+  return typeof module.exports.parse(v) === "string";
+};
+
+module.exports.definition = {
+  set(v) {
+    v = parsers.prepareValue(v, this._global);
+    this._setProperty("width", module.exports.parse(v));
+  },
+  get() {
+    return this.getPropertyValue("width");
+  },
+  enumerable: true,
+  configurable: true
+};