fix(mac): add tailnet discovery fallback and debug CLI

apps/macos/Sources/Clawdbot/OnboardingView+Testing.swift

@@ -1,3 +1,4 @@
+import ClawdbotDiscovery
 import SwiftUI
 
 #if DEBUG
@@ -5,7 +6,7 @@ import SwiftUI
 extension OnboardingView {
     static func exerciseForTesting() {
         let state = AppState(preview: true)
-        let discovery = GatewayDiscoveryModel()
+        let discovery = GatewayDiscoveryModel(localDisplayName: InstanceIdentity.displayName)
         discovery.statusText = "Searching..."
         let gateway = GatewayDiscoveryModel.DiscoveredGateway(
             displayName: "Test Bridge",