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.

1 files changed, 23 insertions, 23 deletions

diff --git a/DomainDig/WatchlistView.swift b/DomainDig/WatchlistView.swift
index 389ae91..5c5609e 100644
--- a/DomainDig/WatchlistView.swift
+++ b/DomainDig/WatchlistView.swift
@@ -38,7 +38,7 @@ struct WatchlistView: View {
                 Section("Refresh Progress") {
                     VStack(alignment: .leading, spacing: 8) {
                         ProgressView(value: Double(viewModel.batchCompletedCount), total: Double(max(viewModel.batchTotalCount, 1)))
-                            .tint(.cyan)
+                            .tint(Color(.statusInfo))
                         HStack {
                             Text(viewModel.batchProgressLabel)
                                 .font(appDensity.font(.caption))
@@ -59,7 +59,7 @@ struct WatchlistView: View {
                     }
                     .padding(.vertical, 4)
                 }
-                .listRowBackground(Color(.systemGray6).opacity(0.5))
+                .listRowBackground(Color(.appSurface))
             }
 
             if viewModel.filteredTrackedDomains.isEmpty {
@@ -72,7 +72,7 @@ struct WatchlistView: View {
                         showsCardBackground: false
                     )
                 }
-                .listRowBackground(Color(.systemGray6).opacity(0.5))
+                .listRowBackground(Color(.appSurface))
             } else {
                 if let limitMessage = FeatureAccessService.trackedDomainLimitMessage(currentCount: viewModel.trackedDomains.count) {
                     Section {
@@ -80,7 +80,7 @@ struct WatchlistView: View {
                             .font(appDensity.font(.caption))
                             .foregroundStyle(.secondary)
                     }
-                    .listRowBackground(Color(.systemGray6).opacity(0.5))
+                    .listRowBackground(Color(.appSurface))
                 }
 
                 if !pinnedDomains.isEmpty {
@@ -94,7 +94,7 @@ struct WatchlistView: View {
         }
         .animation(.easeInOut(duration: 0.2), value: viewModel.filteredTrackedDomains.map(\.id))
         .scrollContentBackground(.hidden)
-        .background(Color.black)
+        .background(Color(.appBackground))
         .navigationTitle("Watchlist")
         .searchable(text: $viewModel.watchlistSearchText, prompt: "Search tracked domains")
         .toolbar {
@@ -215,7 +215,7 @@ struct WatchlistView: View {
                         Section {
                             Text(addDomainError)
                                 .font(appDensity.font(.caption))
-                                .foregroundStyle(.red)
+                                .foregroundStyle(Color(.statusCritical))
                         }
                     }
                 }
@@ -317,14 +317,14 @@ struct WatchlistView: View {
             } label: {
                 Label("Refresh", systemImage: "arrow.clockwise")
             }
-            .tint(.cyan)
+            .tint(Color(.statusInfo))
 
             Button {
                 viewModel.togglePinned(for: trackedDomain)
             } label: {
                 Label(trackedDomain.isPinned ? "Unpin" : "Pin", systemImage: trackedDomain.isPinned ? "pin.slash" : "pin")
             }
-            .tint(.yellow)
+            .tint(Color(.statusWarning))
         }
         .swipeActions(edge: .trailing, allowsFullSwipe: false) {
             Button {
@@ -333,7 +333,7 @@ struct WatchlistView: View {
             } label: {
                 Label("Refresh", systemImage: "arrow.clockwise")
             }
-            .tint(.cyan)
+            .tint(Color(.statusInfo))
 
             if viewModel.canDelete(trackedDomain) {
                 Button(role: .destructive) {
@@ -380,7 +380,7 @@ struct WatchlistView: View {
                 }
             }
         }
-        .listRowBackground(Color(.systemGray6).opacity(0.5))
+        .listRowBackground(Color(.appSurface))
     }
 
     private var batchSummaryBinding: Binding<BatchSweepSummary?> {
@@ -437,7 +437,7 @@ struct WatchlistRowView: View {
                 if trackedDomain.isPinned {
                     Image(systemName: "pin.fill")
                         .font(.caption2)
-                        .foregroundStyle(.yellow)
+                        .foregroundStyle(Color(.statusWarning))
                 }
                 Text(trackedDomain.domain)
                     .font(appDensity.font(.callout))
@@ -502,7 +502,7 @@ struct WatchlistRowView: View {
     @ViewBuilder
     private var statusBadge: some View {
         if isRefreshing {
-            AppStatusBadgeView(model: .init(title: "Refreshing", systemImage: "arrow.clockwise", foregroundColor: .secondary, backgroundColor: Color(.systemGray5).opacity(0.6)))
+            AppStatusBadgeView(model: .init(title: "Refreshing", systemImage: "arrow.clockwise", foregroundColor: .secondary, backgroundColor: Color(.appSurfaceElevated)))
         } else {
             AppStatusBadgeView(model: AppStatusFactory.availability(trackedDomain.lastKnownAvailability))
         }
@@ -516,8 +516,8 @@ struct WatchlistRowView: View {
                     model: .init(
                         title: "Shared",
                         systemImage: "person.2.fill",
-                        foregroundColor: .cyan,
-                        backgroundColor: .cyan.opacity(0.16)
+                        foregroundColor: Color(.statusInfo),
+                        backgroundColor: Color(.statusInfo).opacity(0.16)
                     )
                 )
             }
@@ -534,11 +534,11 @@ struct WatchlistRowView: View {
         let days = trackedDomain.certificateDaysRemaining.map { "\($0)d" } ?? "Soon"
         switch trackedDomain.certificateWarningLevel {
         case .critical:
-            return .init(title: "Invalid \(days)", systemImage: "xmark.octagon.fill", foregroundColor: .red, backgroundColor: .red.opacity(0.16))
+            return .init(title: "Invalid \(days)", systemImage: "xmark.octagon.fill", foregroundColor: Color(.statusCritical), backgroundColor: Color(.statusCritical).opacity(0.16))
         case .warning:
-            return .init(title: "Expiring \(days)", systemImage: "exclamationmark.triangle.fill", foregroundColor: .yellow, backgroundColor: .yellow.opacity(0.16))
+            return .init(title: "Expiring \(days)", systemImage: "exclamationmark.triangle.fill", foregroundColor: Color(.statusWarning), backgroundColor: Color(.statusWarning).opacity(0.16))
         case .none:
-            return .init(title: "Valid", systemImage: "lock.fill", foregroundColor: .green, backgroundColor: .green.opacity(0.16))
+            return .init(title: "Valid", systemImage: "lock.fill", foregroundColor: Color(.statusPositive), backgroundColor: Color(.statusPositive).opacity(0.16))
         }
     }
 }
@@ -577,7 +577,7 @@ struct TrackedDomainDetailView: View {
                     isRefreshing: viewModel.refreshingTrackedDomainID == liveTrackedDomain.id
                 )
             }
-            .listRowBackground(Color(.systemGray6).opacity(0.5))
+            .listRowBackground(Color(.appSurface))
 
             Section {
                 Button {
@@ -652,13 +652,13 @@ struct TrackedDomainDetailView: View {
                     Label(liveTrackedDomain.collaboration?.isShared == true ? "Manage Share" : "Share Domain", systemImage: "person.2")
                 }
             }
-            .listRowBackground(Color(.systemGray6).opacity(0.5))
+            .listRowBackground(Color(.appSurface))
 
             if !liveTrackedDomain.tags.isEmpty {
                 Section("Tags") {
                     TagChipRowView(tags: liveTrackedDomain.tags)
                 }
-                .listRowBackground(Color(.systemGray6).opacity(0.5))
+                .listRowBackground(Color(.appSurface))
             }
 
             Section("Monitoring Status") {
@@ -672,7 +672,7 @@ struct TrackedDomainDetailView: View {
                     LabeledContent("Queued Alerts", value: "\(liveTrackedDomain.pendingMonitoringAlerts.count)")
                 }
             }
-            .listRowBackground(Color(.systemGray6).opacity(0.5))
+            .listRowBackground(Color(.appSurface))
 
             if let summary = viewModel.latestChangeSummary(for: liveTrackedDomain) {
                 Section("Latest Change Summary") {
@@ -718,10 +718,10 @@ struct TrackedDomainDetailView: View {
                     }
                 }
             }
-            .listRowBackground(Color(.systemGray6).opacity(0.5))
+            .listRowBackground(Color(.appSurface))
         }
         .scrollContentBackground(.hidden)
-        .background(Color.black)
+        .background(Color(.appBackground))
         .navigationTitle(liveTrackedDomain.domain)
         .preferredColorScheme(.dark)
         .onChange(of: viewModel.rerunNavigationToken) { _, _ in