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/time.js

@@ -0,0 +1,71 @@
+import {timeYear, timeMonth, timeWeek, timeDay, timeHour, timeMinute, timeSecond, timeTicks, timeTickInterval} from "d3-time";
+import {timeFormat} from "d3-time-format";
+import continuous, {copy} from "./continuous.js";
+import {initRange} from "./init.js";
+import nice from "./nice.js";
+
+function date(t) {
+  return new Date(t);
+}
+
+function number(t) {
+  return t instanceof Date ? +t : +new Date(+t);
+}
+
+export function calendar(ticks, tickInterval, year, month, week, day, hour, minute, second, format) {
+  var scale = continuous(),
+      invert = scale.invert,
+      domain = scale.domain;
+
+  var formatMillisecond = format(".%L"),
+      formatSecond = format(":%S"),
+      formatMinute = format("%I:%M"),
+      formatHour = format("%I %p"),
+      formatDay = format("%a %d"),
+      formatWeek = format("%b %d"),
+      formatMonth = format("%B"),
+      formatYear = format("%Y");
+
+  function tickFormat(date) {
+    return (second(date) < date ? formatMillisecond
+        : minute(date) < date ? formatSecond
+        : hour(date) < date ? formatMinute
+        : day(date) < date ? formatHour
+        : month(date) < date ? (week(date) < date ? formatDay : formatWeek)
+        : year(date) < date ? formatMonth
+        : formatYear)(date);
+  }
+
+  scale.invert = function(y) {
+    return new Date(invert(y));
+  };
+
+  scale.domain = function(_) {
+    return arguments.length ? domain(Array.from(_, number)) : domain().map(date);
+  };
+
+  scale.ticks = function(interval) {
+    var d = domain();
+    return ticks(d[0], d[d.length - 1], interval == null ? 10 : interval);
+  };
+
+  scale.tickFormat = function(count, specifier) {
+    return specifier == null ? tickFormat : format(specifier);
+  };
+
+  scale.nice = function(interval) {
+    var d = domain();
+    if (!interval || typeof interval.range !== "function") interval = tickInterval(d[0], d[d.length - 1], interval == null ? 10 : interval);
+    return interval ? domain(nice(d, interval)) : scale;
+  };
+
+  scale.copy = function() {
+    return copy(scale, calendar(ticks, tickInterval, year, month, week, day, hour, minute, second, format));
+  };
+
+  return scale;
+}
+
+export default function time() {
+  return initRange.apply(calendar(timeTicks, timeTickInterval, timeYear, timeMonth, timeWeek, timeDay, timeHour, timeMinute, timeSecond, timeFormat).domain([new Date(2000, 0, 1), new Date(2000, 0, 2)]), arguments);
+}