Collector health status text: fixed Brushes.OrangeRed fails WCAG contrast on Light theme

[erikdarlingdata]

What happens

Outside the plan viewer, CollectorHealthText.Foreground is set to the fixed
System.Windows.Media.Brushes.OrangeRed (#FF4500) in two places:

• Lite/MainWindow.xaml.cs (erroring collectors, dead XE capture, and a third status this
  same pattern covers)
• Darling/PerformanceMonitor.Darling.Viewer/MainWindow.ServerManagement.cs (same status text)

This is the same fixed, theme-unaware brush #4629 just replaced in the plan viewer for the
same reason: #FF4500 measures 3.44:1 against a white Light background, under WCAG AA's 4.5:1
floor for text, and 4.46:1 against Dark's node background (also just under the floor).

Suggested fix

Route these through the same theme-aware PlanCriticalOrangeBrush / PlanCriticalOrangeColor
resource #4629 added to Lite's, the Dashboard's, and the Darling Viewer's LightTheme.xaml,
DarkTheme.xaml and CoolBreezeTheme.xaml (Light/CoolBreeze #A83A0D, Dark #FF7043, both

= 4.5:1 against every page/card/node background in their theme) — or another theme resource,
if the status bar's background differs enough that those two values don't clear the floor
there too.

Why this wasn't folded into #4629

#4629 was scoped to plan-viewer rendering in PerformanceMonitor.PlanAnalysis and
PerformanceMonitor.Ui. MainWindow.xaml.cs/MainWindow.ServerManagement.cs are each
app's own status-bar code, a different subsystem, not shared between Lite and the Dashboard.

[erikdarlingdata]

Fixed in #4632, folded in alongside the #4629 plan-viewer contrast fix: Lite's and the Darling Viewer's status-bar collector-health text now resolve a theme-aware CriticalTextBrush instead of the fixed Brushes.OrangeRed.

Out of scope: the deprecated Dashboard has the identical pattern (MemoryContent.PlanCache.cs, ResourceMetricsContent.TempdbStats.cs) and its own copy of the plan-viewer theme files, but neither is touched, since the Dashboard is deprecated. git diff --stat origin/dev...HEAD -- deprecated/ on that branch is empty.

[erikdarlingdata]

Claude posting for Erik Darling

Fixed by #4632, merged to dev as 5e0e737. The collector health text in the Lite and Darling Viewer status bars now uses CriticalTextBrush: #A83A0D on Light, which is 6.41:1 on the white status bar. It falls back to OrangeRed where a theme lacks that brush. I checked the code and the contrast tests, not the status bar on screen.