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/backgroundPosition.js

@@ -0,0 +1,52 @@
+"use strict";
+
+const parsers = require("../parsers");
+
+module.exports.parse = function parse(v) {
+  const parts = parsers.splitValue(v);
+  if (!parts.length || parts.length > 2) {
+    return;
+  }
+  const validKeywordsX = ["left", "center", "right"];
+  const validKeywordsY = ["top", "center", "bottom"];
+  if (parts.length === 1) {
+    const dim = parsers.parseMeasurement(parts[0]);
+    if (dim) {
+      return dim;
+    }
+    const validKeywords = new Set([...validKeywordsX, ...validKeywordsY]);
+    return parsers.parseKeyword(v, [...validKeywords]);
+  }
+  const [partX, partY] = parts;
+  const posX = parsers.parseMeasurement(partX) || parsers.parseKeyword(partX, validKeywordsX);
+  if (posX) {
+    const posY = parsers.parseMeasurement(partY) || parsers.parseKeyword(partY, validKeywordsY);
+    if (posY) {
+      return `${posX} ${posY}`;
+    }
+  }
+};
+
+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);
+    if (parsers.hasVarFunc(v)) {
+      this._setProperty("background", "");
+      this._setProperty("background-position", v);
+    } else {
+      this._setProperty("background-position", module.exports.parse(v));
+    }
+  },
+  get() {
+    return this.getPropertyValue("background-position");
+  },
+  enumerable: true,
+  configurable: true
+};