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/padding.js

@@ -0,0 +1,58 @@
+"use strict";
+
+const parsers = require("../parsers");
+
+const positions = ["top", "right", "bottom", "left"];
+
+module.exports.parse = function parse(v) {
+  const val = parsers.parseMeasurement(v, true);
+  if (val) {
+    return val;
+  }
+  return parsers.parseKeyword(v);
+};
+
+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._implicitSetter(
+        "padding",
+        "",
+        "",
+        module.exports.isValid,
+        module.exports.parse,
+        positions
+      );
+      this._setProperty("padding", v);
+    } else {
+      this._implicitSetter(
+        "padding",
+        "",
+        v,
+        module.exports.isValid,
+        module.exports.parse,
+        positions
+      );
+    }
+  },
+  get() {
+    const val = this._implicitGetter("padding", positions);
+    if (val === "") {
+      return this.getPropertyValue("padding");
+    }
+    if (parsers.hasVarFunc(val)) {
+      return "";
+    }
+    return val;
+  },
+  enumerable: true,
+  configurable: true
+};