fix(macos): sync node pairing approvals

apps/macos/Sources/Clawdis/TerminationSignalWatcher.swift

@@ -0,0 +1,52 @@
+import AppKit
+import Foundation
+import OSLog
+
+@MainActor
+final class TerminationSignalWatcher {
+    static let shared = TerminationSignalWatcher()
+
+    private let logger = Logger(subsystem: "com.steipete.clawdis", category: "lifecycle")
+    private var sources: [DispatchSourceSignal] = []
+    private var terminationRequested = false
+
+    func start() {
+        guard self.sources.isEmpty else { return }
+        self.install(SIGTERM)
+        self.install(SIGINT)
+    }
+
+    func stop() {
+        for s in self.sources {
+            s.cancel()
+        }
+        self.sources.removeAll(keepingCapacity: false)
+        self.terminationRequested = false
+    }
+
+    private func install(_ sig: Int32) {
+        // Make sure the default action doesn't kill the process before we can gracefully shut down.
+        signal(sig, SIG_IGN)
+        let source = DispatchSource.makeSignalSource(signal: sig, queue: .main)
+        source.setEventHandler { [weak self] in
+            self?.handle(sig)
+        }
+        source.resume()
+        self.sources.append(source)
+    }
+
+    private func handle(_ sig: Int32) {
+        guard !self.terminationRequested else { return }
+        self.terminationRequested = true
+
+        self.logger.info("received signal \(sig, privacy: .public); terminating")
+        // Ensure any pairing prompt can't accidentally approve during shutdown.
+        NodePairingApprovalPrompter.shared.stop()
+        NSApp.terminate(nil)
+
+        // Safety net: don't hang forever if something blocks termination.
+        DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
+            exit(0)
+        }
+    }
+}