feat: add in-app Sparkle update logging

- Add published logMessages array to SparkleUpdater to track all update events
- Display logs in the Updates preferences tab with Show/Hide toggle
- Each log entry is timestamped and shows both info and error messages
- Logs persist during session with max 100 entries
- Users can clear logs manually
- Helps diagnose update failures directly in the app UI

Sources/ViewModels/SparkleUpdater.swift

@@ -9,6 +9,8 @@ final class SparkleUpdater: NSObject, ObservableObject {
     }()
     private let logger = Logger(subsystem: "net.24unix.iKeyMon", category: "Sparkle")
     private let verboseLogging: Bool
+    @Published var logMessages: [String] = []
+    @Published var showLogs: Bool = false
 
     override init() {
         self.verboseLogging = ProcessInfo.processInfo.environment["SPARKLE_VERBOSE_LOGGING"] == "1"
@@ -34,6 +36,7 @@ final class SparkleUpdater: NSObject, ObservableObject {
 
     private func log(_ message: String) {
         logger.log("\(message, privacy: .public)")
+        addLogMessage("[INFO] \(message)")
         if verboseLogging {
             print("[Sparkle] \(message)")
         }
@@ -41,11 +44,21 @@ final class SparkleUpdater: NSObject, ObservableObject {
 
     private func logError(_ message: String) {
         logger.error("\(message, privacy: .public)")
+        addLogMessage("[ERROR] \(message)")
         if verboseLogging {
             fputs("[Sparkle][error] \(message)\n", stderr)
         }
     }
 
+    private func addLogMessage(_ message: String) {
+        let timestamp = DateFormatter.localizedString(from: Date(), dateStyle: .none, timeStyle: .medium)
+        let timestampedMessage = "[\(timestamp)] \(message)"
+        logMessages.append(timestampedMessage)
+        if logMessages.count > 100 {
+            logMessages.removeFirst()
+        }
+    }
+
     private func describe(update item: SUAppcastItem) -> String {
         let short = item.displayVersionString
         let build = item.versionString
@@ -53,41 +66,58 @@ final class SparkleUpdater: NSObject, ObservableObject {
     }
 }
 
-@MainActor
 extension SparkleUpdater: SPUUpdaterDelegate {
-    func updater(_ updater: SPUUpdater, didFinishLoading appcast: SUAppcast) {
-        log("Loaded Sparkle appcast containing \(appcast.items.count) item(s).")
+    nonisolated func updater(_ updater: SPUUpdater, didFinishLoading appcast: SUAppcast) {
+        Task { @MainActor in
+            log("Loaded Sparkle appcast containing \(appcast.items.count) item(s).")
+        }
     }
 
-    func updater(_ updater: SPUUpdater, didFindValidUpdate item: SUAppcastItem) {
-        log("Found valid update \(describe(update: item))")
+    nonisolated func updater(_ updater: SPUUpdater, didFindValidUpdate item: SUAppcastItem) {
+        Task { @MainActor in
+            log("Found valid update \(describe(update: item))")
+        }
     }
 
-    func updaterDidNotFindUpdate(_ updater: SPUUpdater) {
-        log("No updates available.")
+    nonisolated func updaterDidNotFindUpdate(_ updater: SPUUpdater) {
+        Task { @MainActor in
+            log("No updates available.")
+        }
     }
 
-    func updater(_ updater: SPUUpdater, willDownloadUpdate item: SUAppcastItem, with request: NSMutableURLRequest) {
-        log("Downloading \(describe(update: item)) from \(request.url?.absoluteString ?? "unknown URL")")
+    nonisolated func updater(_ updater: SPUUpdater, willDownloadUpdate item: SUAppcastItem, with request: NSMutableURLRequest) {
+        Task { @MainActor in
+            log("Downloading \(describe(update: item)) from \(request.url?.absoluteString ?? "unknown URL")")
+        }
     }
 
-    func updater(_ updater: SPUUpdater, didDownloadUpdate item: SUAppcastItem) {
-        log("Finished downloading \(describe(update: item))")
+    nonisolated func updater(_ updater: SPUUpdater, didDownloadUpdate item: SUAppcastItem) {
+        Task { @MainActor in
+            log("Finished downloading \(describe(update: item))")
+        }
     }
 
-    func updater(_ updater: SPUUpdater, failedToDownloadUpdate item: SUAppcastItem, error: Error) {
-        logError("Failed to download \(describe(update: item)): \(error.localizedDescription)")
+    nonisolated func updater(_ updater: SPUUpdater, failedToDownloadUpdate item: SUAppcastItem, error: Error) {
+        Task { @MainActor in
+            logError("Failed to download \(describe(update: item)): \(error.localizedDescription)")
+        }
     }
 
-    func userDidCancelDownload(_ updater: SPUUpdater) {
-        log("User cancelled Sparkle download.")
+    nonisolated func userDidCancelDownload(_ updater: SPUUpdater) {
+        Task { @MainActor in
+            log("User cancelled Sparkle download.")
+        }
     }
 
-    func updater(_ updater: SPUUpdater, willInstallUpdate item: SUAppcastItem) {
-        log("Will install update \(describe(update: item))")
+    nonisolated func updater(_ updater: SPUUpdater, willInstallUpdate item: SUAppcastItem) {
+        Task { @MainActor in
+            log("Will install update \(describe(update: item))")
+        }
     }
 
-    func updater(_ updater: SPUUpdater, didAbortWithError error: Error) {
-        logError("Sparkle aborted: \(error.localizedDescription)")
+    nonisolated func updater(_ updater: SPUUpdater, didAbortWithError error: Error) {
+        Task { @MainActor in
+            logError("Sparkle aborted: \(error.localizedDescription)")
+        }
     }
 }

Sources/Views/PreferencesView.swift

@@ -257,11 +257,64 @@ private struct UpdatesPreferencesView: View {
                 .foregroundColor(.secondary)
                 .padding(.top, 4)
 
+            Divider()
+                .padding(.vertical, 8)
+
+            Button(action: { sparkleUpdater.showLogs.toggle() }) {
+                Label(sparkleUpdater.showLogs ? "Hide Logs" : "Show Logs", systemImage: "terminal.fill")
+            }
+
+            if sparkleUpdater.showLogs {
+                logsView
+            }
+
             Spacer()
         }
         .toggleStyle(.switch)
         .frame(maxWidth: .infinity, alignment: .leading)
     }
+
+    private var logsView: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            Text("Update Logs")
+                .font(.caption)
+                .fontWeight(.semibold)
+                .foregroundColor(.secondary)
+
+            ScrollView {
+                VStack(alignment: .leading, spacing: 4) {
+                    if sparkleUpdater.logMessages.isEmpty {
+                        Text("No logs yet. Check for updates to see activity.")
+                            .font(.caption)
+                            .foregroundColor(.secondary)
+                            .italic()
+                    } else {
+                        ForEach(sparkleUpdater.logMessages, id: \.self) { message in
+                            Text(message)
+                                .font(.caption)
+                                .foregroundColor(.secondary)
+                                .lineLimit(3)
+                                .textSelection(.enabled)
+                        }
+                    }
+                }
+                .frame(maxWidth: .infinity, alignment: .leading)
+                .padding(8)
+            }
+            .frame(height: 200)
+            .background(Color(nsColor: .controlBackgroundColor))
+            .cornerRadius(6)
+            .border(.separator, width: 1)
+
+            Button(action: {
+                sparkleUpdater.logMessages.removeAll()
+            }) {
+                Label("Clear Logs", systemImage: "trash")
+                    .font(.caption)
+            }
+            .disabled(sparkleUpdater.logMessages.isEmpty)
+        }
+    }
 }
 
 private struct NotificationsPreferencesView: View {