feat(a11y): semantic colour system (#21 phase 1)

Replaces every hard-coded colour with semantic asset colours that adapt to
light, dark, and Increase Contrast. Dark mode stays locked, so this is a
pure refactor: the audit reports the same findings before and after.

The accent is now blue rather than cyan, per the tech/DNS theme.

Why custom values rather than the system palette: every system colour
fails WCAG AA in light mode. Measured on white — systemYellow 1.51:1,
systemOrange 2.20:1, systemGreen 2.22:1, systemCyan 2.54:1, systemRed
3.55:1. All of them pass in dark mode, which is why the dark-locked app
looked fine, and why unlocking light mode was never a matter of deleting
.preferredColorScheme(.dark). Every new value clears 4.5:1 as text on its
page, its card, and its own 16% badge tint — the way AppStatusBadgeView
actually draws it.

The accent needed splitting in two. As text on a dark background it must
be light; as a fill behind a white label it must be dark. #4DA3FF reads
8.00:1 as text on black but 2.63:1 behind white text, so StatusInfo /
AccentColor cover the foreground role and AccentFill covers
.borderedProminent. AppOnAccent is the label colour for a solid fill and
flips by scheme.

Colours live in Shared/Colors.xcassets rather than the app catalog: the
Shared folder is already a synchronized group in all three targets, so
the widget and share extension pick the palette up with no project-file
surgery. AccentColor stays in the app catalog as the global tint — and is
now actually defined, having been an empty colorset that silently left
system controls rendering in stock blue while custom chrome used cyan.

Two deliberate visual changes: orange folds into StatusWarning and pink
into StatusCritical. They encoded the same severity as the colours they
now share, and both sites also carry a text label.

Audit findings drop 15 to 14, and one of the originals turned out to be
a phantom: the Inspect contrast failure was the Run button in its
disabled state, which WCAG 1.4.3 exempts. testInspectScreen now types a
domain first so the audit measures an enabled control. Findings also
carry the offending element now, so the remaining clipped-text items name
themselves ("No Portfolio Yet", "Search domains") instead of being
anonymous.

2 files changed, 16 insertions, 16 deletions

diff --git a/DomainDigWidget/DomainDigPortfolioWidget.swift b/DomainDigWidget/DomainDigPortfolioWidget.swift
index bc88ac0..a3335c8 100644
--- a/DomainDigWidget/DomainDigPortfolioWidget.swift
+++ b/DomainDigWidget/DomainDigPortfolioWidget.swift
@@ -91,9 +91,9 @@ struct DomainDigWidgetView: View {
             Spacer(minLength: 0)
 
             HStack(spacing: 10) {
-                countPill(data.healthyCount, .green)
-                countPill(data.warningCount, .orange)
-                countPill(data.criticalCount, .red)
+                countPill(data.healthyCount, Color(.statusPositive))
+                countPill(data.warningCount, Color(.statusWarning))
+                countPill(data.criticalCount, Color(.statusCritical))
             }
         }
     }
@@ -121,10 +121,10 @@ struct DomainDigWidgetView: View {
             }
 
             HStack(spacing: 12) {
-                summaryStat(data.healthyCount, "Healthy", .green)
-                summaryStat(data.warningCount, "Warning", .orange)
-                summaryStat(data.criticalCount, "Critical", .red)
-                summaryStat(data.expiringSoonCount, "Expiring", .yellow)
+                summaryStat(data.healthyCount, "Healthy", Color(.statusPositive))
+                summaryStat(data.warningCount, "Warning", Color(.statusWarning))
+                summaryStat(data.criticalCount, "Critical", Color(.statusCritical))
+                summaryStat(data.expiringSoonCount, "Expiring", Color(.statusWarning))
             }
 
             Divider()
@@ -180,9 +180,9 @@ struct DomainDigWidgetView: View {
 
     private func color(for status: DomainDigWidgetStatus) -> Color {
         switch status {
-        case .healthy: return .green
-        case .warning: return .orange
-        case .critical: return .red
+        case .healthy: return Color(.statusPositive)
+        case .warning: return Color(.statusWarning)
+        case .critical: return Color(.statusCritical)
         }
     }
 }
diff --git a/DomainDigWidget/SweepLiveActivity.swift b/DomainDigWidget/SweepLiveActivity.swift
index b99a070..b96f8bf 100644
--- a/DomainDigWidget/SweepLiveActivity.swift
+++ b/DomainDigWidget/SweepLiveActivity.swift
@@ -24,7 +24,7 @@ struct SweepLiveActivity: Widget {
                 DynamicIslandExpandedRegion(.bottom) {
                     VStack(alignment: .leading, spacing: 4) {
                         ProgressView(value: context.state.fractionComplete)
-                            .tint(.cyan)
+                            .tint(Color(.statusInfo))
                         if let current = context.state.currentDomain {
                             Text(current)
                                 .font(.caption2)
@@ -35,7 +35,7 @@ struct SweepLiveActivity: Widget {
                 }
             } compactLeading: {
                 Image(systemName: "arrow.trianglehead.2.clockwise")
-                    .foregroundStyle(.cyan)
+                    .foregroundStyle(Color(.statusInfo))
             } compactTrailing: {
                 Text("\(context.state.completed)/\(context.state.total)")
                     .font(.caption2)
@@ -43,7 +43,7 @@ struct SweepLiveActivity: Widget {
             } minimal: {
                 ProgressView(value: context.state.fractionComplete)
                     .progressViewStyle(.circular)
-                    .tint(.cyan)
+                    .tint(Color(.statusInfo))
             }
         }
     }
@@ -66,7 +66,7 @@ private struct SweepActivityBannerView: View {
             }
 
             ProgressView(value: context.state.fractionComplete)
-                .tint(.cyan)
+                .tint(Color(.statusInfo))
 
             HStack {
                 if let current = context.state.currentDomain {
@@ -83,12 +83,12 @@ private struct SweepActivityBannerView: View {
                 if context.state.changed > 0 {
                     Text("\(context.state.changed) changed")
                         .font(.caption2)
-                        .foregroundStyle(.orange)
+                        .foregroundStyle(Color(.statusWarning))
                 }
                 if context.state.warnings > 0 {
                     Text("\(context.state.warnings) warnings")
                         .font(.caption2)
-                        .foregroundStyle(.red)
+                        .foregroundStyle(Color(.statusCritical))
                 }
             }
         }