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/d3-scale/src/symlog.js

@@ -0,0 +1,35 @@
+import {linearish} from "./linear.js";
+import {copy, transformer} from "./continuous.js";
+import {initRange} from "./init.js";
+
+function transformSymlog(c) {
+  return function(x) {
+    return Math.sign(x) * Math.log1p(Math.abs(x / c));
+  };
+}
+
+function transformSymexp(c) {
+  return function(x) {
+    return Math.sign(x) * Math.expm1(Math.abs(x)) * c;
+  };
+}
+
+export function symlogish(transform) {
+  var c = 1, scale = transform(transformSymlog(c), transformSymexp(c));
+
+  scale.constant = function(_) {
+    return arguments.length ? transform(transformSymlog(c = +_), transformSymexp(c)) : c;
+  };
+
+  return linearish(scale);
+}
+
+export default function symlog() {
+  var scale = symlogish(transformer());
+
+  scale.copy = function() {
+    return copy(scale, symlog()).constant(scale.constant());
+  };
+
+  return initRange.apply(scale, arguments);
+}