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, 68 insertions, 0 deletions

diff --git a/DomainDig/BatchSweepSummaryView.swift b/DomainDig/BatchSweepSummaryView.swift
new file mode 100644
index 0000000..fda2bc5
--- /dev/null
+++ b/DomainDig/BatchSweepSummaryView.swift
@@ -0,0 +1,68 @@
+import SwiftUI
+
+struct BatchSweepSummaryView: View {
+    @Bindable var viewModel: DomainViewModel
+    let summary: BatchSweepSummary
+
+    @State private var showUnchangedDomains = false
+
+    private var visibleResults: [BatchLookupResult] {
+        if showUnchangedDomains {
+            return summary.results
+        }
+
+        return summary.results.filter {
+            ($0.changeSeverity ?? .low) >= .medium || $0.certificateWarningLevel != .none || $0.status == .failed
+        }
+    }
+
+    var body: some View {
+        NavigationStack {
+            List {
+                Section("Overview") {
+                    statRow(label: "Checked", value: "\(summary.totalDomains)")
+                    statRow(label: "Changed", value: "\(summary.changedDomains)")
+                    statRow(label: "Warnings", value: "\(summary.warningDomains)")
+                    statRow(label: "Unchanged", value: "\(summary.unchangedDomains)")
+                }
+
+                Section {
+                    Toggle("Show unchanged domains", isOn: $showUnchangedDomains)
+                }
+
+                Section(visibleResults.isEmpty ? "Changed Domains" : "Results") {
+                    if visibleResults.isEmpty {
+                        Text("No domains with changes or warnings")
+                            .font(.system(.caption, design: .monospaced))
+                            .foregroundStyle(.secondary)
+                    } else {
+                        ForEach(visibleResults) { result in
+                            if let entry = viewModel.historyEntry(for: result) {
+                                NavigationLink {
+                                    HistoryDetailView(viewModel: viewModel, entry: entry)
+                                } label: {
+                                    BatchResultRowView(result: result)
+                                }
+                            } else {
+                                BatchResultRowView(result: result)
+                            }
+                        }
+                    }
+                }
+            }
+            .navigationTitle(summary.source == .watchlistRefresh ? "Sweep Summary" : "Batch Summary")
+        }
+    }
+
+    private func statRow(label: String, value: String) -> some View {
+        HStack {
+            Text(label)
+                .font(.system(.caption, design: .monospaced))
+                .foregroundStyle(.secondary)
+            Spacer()
+            Text(value)
+                .font(.system(.callout, design: .monospaced))
+                .foregroundStyle(.primary)
+        }
+    }
+}