feat: add stacked progress bar for parent jobs with sub-job breakdown

Parent jobs with fetched sub-jobs now show a multi-color stacked
progress bar instead of the single parent-progress bar. Segments
represent sub-job status distribution: completed (success),
running (primary), waiting (info), failed (danger), with-errors
(warning), and queued (primary for visibility in dark theme).

ProgressBar gets an optional Segments parameter for stacked mode.
JobRow accepts Children and computes status-weighted segments.
JobTree passes cached children to JobRow.

MilkStream.Client/Components/JobRow.razor

@@ -17,7 +17,11 @@
             <span class="text-truncate text-muted small text-end">@(Job.Started?.ToLocalTime().ToString("g")) &mdash; @(Job.Finished?.ToLocalTime().ToString("g"))</span>
         } else {
             <span class="flex-shrink-0" style="width: 90px;">
-                <ProgressBar Value="@Job.Progress" Color="@StatusColor" />
+                @if (_segments is not null) {
+                    <ProgressBar Segments="@_segments" />
+                } else {
+                    <ProgressBar Value="@Job.Progress" Color="@StatusColor" />
+                }
             </span>
         }
         <span class="flex-shrink-0 text-muted small" style="width: 60px; text-align: right;">@Elapsed</span>
@@ -55,6 +59,46 @@
     [Parameter] public string? ChildSummaryText { get; set; }
     [Parameter] public bool IsExpanded { get; set; }
     [Parameter] public EventCallback<bool> ExpandedChanged { get; set; }
+    [Parameter] public IReadOnlyList<JobStatusDto>? Children { get; set; }
+
+    static readonly Dictionary<EJobStatus, string> _statusColors = new() {
+        [EJobStatus.Queued] = "primary",
+        [EJobStatus.Running] = "primary",
+        [EJobStatus.Waiting] = "info",
+        [EJobStatus.Completed] = "success",
+        [EJobStatus.CompletedWithErrors] = "warning",
+        [EJobStatus.Failed] = "danger",
+        [EJobStatus.Canceled] = "secondary",
+    };
+
+    static readonly EJobStatus[] _segmentOrder = [
+        EJobStatus.Completed,
+        EJobStatus.CompletedWithErrors,
+        EJobStatus.Failed,
+        EJobStatus.Canceled,
+        EJobStatus.Running,
+        EJobStatus.Waiting,
+        EJobStatus.Queued,
+    ];
+
+    List<(float Width, string Color)>? _segments;
+
+    protected override void OnParametersSet() {
+        _segments = ComputeSegments();
+    }
+
+    List<(float Width, string Color)>? ComputeSegments() {
+        if (Children is not { Count: > 0 }) return null;
+
+        var total = (float)Children.Count;
+        var ordered = _segmentOrder
+            .Select(s => (Status: s, Children.Where(c => c.Status == s).ToList()))
+            .Where(g => g.Item2.Count > 0)
+            .Select(g => (g.Item2.Count / total, _statusColors[g.Status]))
+            .ToList();
+
+        return ordered;
+    }
 
     string Icon => Job.JobType switch {
         EJobType.FileSystemScan      => "<i class=\"bi bi-folder2-open\"></i>",

MilkStream.Client/Components/JobTree.razor

@@ -13,6 +13,7 @@
                 Job="root"
                 Level="@Level"
                 ChildSummaryText="@ChildSummary(root, hasFetched, children)"
+                Children="@(hasFetched ? children : null)"
                 IsExpanded="@(_expandedParents.Contains(root.Id) && hasFetched)"
                 ExpandedChanged="(bool e) => OnExpanded(root, e)" />
 

MilkStream.Client/Components/ProgressBar.razor

@@ -1,15 +1,26 @@
-@* Generic progress bar. Value: 0.0 to 1.0. Color: Bootstrap color name (primary, success, etc). Size: sm (default), md, lg. *@
-<div class="progress" role="progressbar" style="height: @Height">
-    <div class="progress-bar @BgClass" style="width: @(Value * 100)%">
-        @if (ShowPercent) { @($"{Value * 100:F0}%") }
+@* Generic progress bar. Value: 0.0 to 1.0. Color: Bootstrap color name (primary, success, etc). Size: sm (default), md, lg. Segments for stacked mode. *@
+@if (Segments is not null and { Count: > 0 }) {
+    <div class="progress-stacked" style="height: @Height">
+        @foreach (var seg in Segments) {
+            <div class="progress" role="progressbar" style="width: @(seg.Width * 100)%">
+                <div class="progress-bar @(SegmentClass(seg.Color))"></div>
+            </div>
+        }
     </div>
-</div>
+} else {
+    <div class="progress" role="progressbar" style="height: @Height">
+        <div class="progress-bar @BgClass" style="width: @(Value * 100)%">
+            @if (ShowPercent) { @($"{Value * 100:F0}%") }
+        </div>
+    </div>
+}
 
 @code {
     [Parameter] public float Value { get; set; }
     [Parameter] public string? Color { get; set; }
     [Parameter] public bool ShowPercent { get; set; }
     [Parameter] public string Size { get; set; } = "sm";
+    [Parameter] public IReadOnlyList<(float Width, string Color)>? Segments { get; set; }
 
     string Height => Size switch {
         "sm" => "6px",
@@ -28,4 +39,15 @@
         "dark" => "text-bg-dark",
         var c => $"bg-{c}"
     };
+
+    string SegmentClass(string color) => color switch {
+        "primary" => "bg-primary",
+        "success" => "bg-success",
+        "danger" => "bg-danger",
+        "warning" => "bg-warning",
+        "info" => "bg-info",
+        "secondary" => "bg-secondary",
+        "dark" => "bg-dark",
+        var c => $"bg-{c}"
+    };
 }