feat(v2.2.0): add foreground monitoring, notifications, and smarter diffs

- implement “Check All” sweep for tracked domains
- add local notifications for changes and certificate expiration
- introduce change severity filtering (low/medium/high)
- enhance change summaries and diff readability
- add certificate expiration tracking and alerts
- improve watchlist indicators for changes
- add sweep summary screen
- optimize performance for larger watchlists

1 files changed, 63 insertions, 5 deletions

diff --git a/DomainDig/WatchlistView.swift b/DomainDig/WatchlistView.swift
index b01b8f9..1f03a0d 100644
--- a/DomainDig/WatchlistView.swift
+++ b/DomainDig/WatchlistView.swift
@@ -9,12 +9,20 @@ struct WatchlistView: View {
             if viewModel.batchLookupSource == .watchlistRefresh, (!viewModel.batchResults.isEmpty || viewModel.batchLookupRunning) {
                 Section("Refresh Progress") {
                     VStack(alignment: .leading, spacing: 8) {
-                        if viewModel.batchLookupRunning {
-                            ProgressView(value: Double(viewModel.batchCompletedCount), total: Double(max(viewModel.batchTotalCount, 1)))
-                                .tint(.cyan)
+                        ProgressView(value: Double(viewModel.batchCompletedCount), total: Double(max(viewModel.batchTotalCount, 1)))
+                            .tint(.cyan)
+                        HStack {
                             Text(viewModel.batchProgressLabel)
                                 .font(.system(.caption, design: .monospaced))
                                 .foregroundStyle(.secondary)
+                            Spacer()
+                            if viewModel.batchLookupRunning {
+                                Button("Cancel") {
+                                    viewModel.cancelBatchLookup()
+                                }
+                                .buttonStyle(.bordered)
+                                .font(.system(.caption2, design: .monospaced))
+                            }
                         }
 
                         ForEach(viewModel.batchResults.prefix(5)) { result in
@@ -129,9 +137,10 @@ struct WatchlistView: View {
                             }
                         }
 
-                        Button("Refresh All") {
+                        Button(viewModel.batchLookupRunning ? "Check All Running" : "Check All") {
                             viewModel.refreshAllTrackedDomains()
                         }
+                        .disabled(viewModel.batchLookupRunning)
 
                         Button("Export TXT") {
                             shareTrackedDomains(asCSV: false)
@@ -151,9 +160,19 @@ struct WatchlistView: View {
         .onChange(of: viewModel.rerunNavigationToken) { _, _ in
             dismiss()
         }
+        .sheet(item: batchSummaryBinding) { summary in
+            BatchSweepSummaryView(viewModel: viewModel, summary: summary)
+        }
         .preferredColorScheme(.dark)
     }
 
+    private var batchSummaryBinding: Binding<BatchSweepSummary?> {
+        Binding(
+            get: { viewModel.latestBatchSweepSummary },
+            set: { viewModel.latestBatchSweepSummary = $0 }
+        )
+    }
+
     private func deleteFilteredTrackedDomains(at offsets: IndexSet) {
         let domains = offsets.map { viewModel.filteredTrackedDomains[$0] }
         domains.forEach(viewModel.deleteTrackedDomain)
@@ -197,13 +216,15 @@ struct WatchlistRowView: View {
                 .font(.system(.caption2, design: .monospaced))
                 .foregroundStyle(.secondary)
 
+            indicatorRow
+
             if let note = trackedDomain.note?.trimmingCharacters(in: .whitespacesAndNewlines), !note.isEmpty {
                 Text(note)
                     .font(.system(.caption, design: .monospaced))
                     .foregroundStyle(.secondary)
                     .lineLimit(2)
             } else if let summary = trackedDomain.lastChangeSummary {
-                Text(summary.changedSections.isEmpty ? "No meaningful changes detected." : summary.changedSections.joined(separator: " • "))
+                Text(summary.message)
                     .font(.system(.caption, design: .monospaced))
                     .foregroundStyle(.secondary)
                     .lineLimit(2)
@@ -270,6 +291,43 @@ struct WatchlistRowView: View {
             return Color(.systemGray5).opacity(0.6)
         }
     }
+
+    @ViewBuilder
+    private var indicatorRow: some View {
+        HStack(spacing: 8) {
+            if let severity = trackedDomain.lastChangeSeverity, severity >= .medium {
+                Label(severity.title, systemImage: severity == .high ? "exclamationmark.circle.fill" : "circle.fill")
+                    .font(.system(.caption2, design: .monospaced))
+                    .foregroundStyle(severity == .high ? .red : .yellow)
+            } else {
+                Label("Stable", systemImage: "circle.fill")
+                    .font(.system(.caption2, design: .monospaced))
+                    .foregroundStyle(.secondary)
+            }
+
+            if trackedDomain.certificateWarningLevel != .none {
+                Text(certificateLabel)
+                    .font(.system(.caption2, design: .monospaced))
+                    .foregroundStyle(trackedDomain.certificateWarningLevel == .critical ? .red : .yellow)
+                    .padding(.horizontal, 8)
+                    .padding(.vertical, 4)
+                    .background((trackedDomain.certificateWarningLevel == .critical ? Color.red : Color.yellow).opacity(0.16))
+                    .clipShape(Capsule())
+            }
+        }
+    }
+
+    private var certificateLabel: String {
+        let days = trackedDomain.certificateDaysRemaining.map { "\($0)d" } ?? "Soon"
+        switch trackedDomain.certificateWarningLevel {
+        case .critical:
+            return "Cert \(days)"
+        case .warning:
+            return "Warn \(days)"
+        case .none:
+            return ""
+        }
+    }
 }
 
 struct TrackedDomainDetailView: View {