fix(macOS): harden mobile surface kind mapping

Packages/Shared/CMUXMobileCore/Sources/CMUXMobileCore/MobileSurfaceKind.swift

@@ -45,4 +45,12 @@ public struct MobileSurfaceKind: RawRepresentable, Codable, Hashable, Sendable {
     public static let todo = MobileSurfaceKind(rawValue: "todo")
     /// A transient Cloud VM loading surface.
     public static let cloudVMLoading = MobileSurfaceKind(rawValue: "cloudVMLoading")
+    /// A native Apple Simulator surface, rendered as a fallback card on mobile.
+    public static let simulator = MobileSurfaceKind(rawValue: "simulator")
+    /// A notifications surface, rendered as a fallback card on mobile.
+    public static let notifications = MobileSurfaceKind(rawValue: "notifications")
+    /// A transient iPhone pairing surface, rendered as a fallback card on mobile.
+    public static let mobilePairing = MobileSurfaceKind(rawValue: "mobilePairing")
+    /// A transient account sign-in surface, rendered as a fallback card on mobile.
+    public static let accountSignIn = MobileSurfaceKind(rawValue: "accountSignIn")
 }

Packages/Shared/CMUXMobileCore/Tests/CMUXMobileCoreTests/MobileStateSyncFrameCodingTests.swift

@@ -101,6 +101,21 @@ struct MobileStateSyncFrameCodingTests {
         #expect(try JSONDecoder().decode(MobileSurfaceKind.self, from: data) == kind)
     }
 
+    @Test func knownFallbackKindsUseStableWireValues() {
+        // These Mac panel kinds intentionally use the open-vocabulary fallback
+        // renderer on phones until a native mobile renderer is available.
+        let kinds: [(MobileSurfaceKind, String)] = [
+            (.simulator, "simulator"),
+            (.notifications, "notifications"),
+            (.mobilePairing, "mobilePairing"),
+            (.accountSignIn, "accountSignIn"),
+        ]
+
+        for (kind, expectedRawValue) in kinds {
+            #expect(kind.rawValue == expectedRawValue)
+        }
+    }
+
     @Test func workspaceRecordWithoutSurfacesDecodesAndReencodesWithoutTheField() throws {
         let json = #"{"id":"ws-old","title":"old","is_selected":false,"is_pinned":false,"last_activity_at":1,"has_unread":false,"sort_index":0,"terminals":[]}"#
         let decoded = try MobileSyncFrameCoder().decode(

Sources/TerminalController+MobileSurfaces.swift

@@ -6,43 +6,12 @@ import Foundation
 /// Mobile surface inventory and focus support kept outside `TerminalController.swift`.
 extension TerminalController {
     /// Maps an app panel kind to the shared, open mobile wire vocabulary.
+    ///
+    /// ``Workspace.surfaceKind(for:)`` is the canonical mapping used by Mac
+    /// workspace snapshots. Reusing it here keeps mobile descriptors and Mac
+    /// persistence on one exhaustive source of truth as panel kinds evolve.
     func mobileSurfaceKind(for panelType: PanelType) -> MobileSurfaceKind {
-        switch panelType {
-        case .terminal:
-            return .terminal
-        case .browser:
-            return .browser
-        case .markdown:
-            return .markdown
-        case .filePreview:
-            return .filePreview
-        case .rightSidebarTool:
-            return .rightSidebarTool
-        case .customSidebar:
-            return .customSidebar
-        case .agentSession:
-            return .agentSession
-        case .project:
-            return .project
-        case .extensionBrowser:
-            return .extensionBrowser
-        case .workspaceTodo:
-            return .todo
-        case .notifications:
-            // Notifications use the open-vocabulary fallback until the phone
-            // provides a native renderer for this panel kind.
-            return MobileSurfaceKind(rawValue: "notifications")
-        case .cloudVMLoading:
-            return .cloudVMLoading
-        case .simulator:
-            // Open wire vocabulary: phones without a native renderer show the
-            // fallback card for this kind (design: unknown kinds stay cards).
-            return MobileSurfaceKind(rawValue: "simulator")
-        case .mobilePairing:
-            return MobileSurfaceKind(rawValue: "mobilePairing")
-        case .accountSignIn:
-            return MobileSurfaceKind(rawValue: "accountSignIn")
-        }
+        MobileSurfaceKind(rawValue: Workspace.surfaceKind(for: panelType))
     }
 
     /// Builds the stable, spatially ordered mobile descriptors for every panel.

cmuxTests/MobileSurfaceKindMappingTests.swift

@@ -24,6 +24,10 @@ import Testing
         .extensionBrowser: "extensionBrowser",
         .workspaceTodo: "todo",
         .cloudVMLoading: "cloudVMLoading",
+        .simulator: "simulator",
+        .notifications: "notifications",
+        .mobilePairing: "mobilePairing",
+        .accountSignIn: "accountSignIn",
     ]
 
     @Test func everyPanelTypeMapsToItsCanonicalWireKind() throws {