macOS: save effective fullscreen styles

macos/Sources/Features/Terminal/BaseTerminalController.swift

@@ -66,6 +66,24 @@ class BaseTerminalController: NSWindowController,
     /// Fullscreen state management.
     private(set) var fullscreenStyle: FullscreenStyle?
 
+    /// The current effective fullscreen mode.
+    /// This is non-nil only while the window is in fullscreen.
+    var effectiveFullscreenMode: FullscreenMode? {
+        guard let fullscreenStyle, fullscreenStyle.isFullscreen else {
+            return nil
+        }
+
+        switch fullscreenStyle {
+        case is NativeFullscreen: return .native
+        case is NonNativeFullscreen: return .nonNative
+        case is NonNativeFullscreenPaddedNotch: return .nonNativePaddedNotch
+        case is NonNativeFullscreenVisibleMenu: return .nonNativeVisibleMenu
+        default:
+            assertionFailure("Missing case here")
+            return nil
+        }
+    }
+
     /// Event monitor (see individual events for why)
     private var eventMonitor: Any? = nil
 

macos/Sources/Features/Terminal/TerminalRestorable.swift

@@ -8,10 +8,12 @@ class TerminalRestorableState: Codable {
 
     let focusedSurface: String?
     let surfaceTree: SplitTree<Ghostty.SurfaceView>
+    let effectiveFullscreenMode: FullscreenMode?
 
     init(from controller: TerminalController) {
         self.focusedSurface = controller.focusedSurface?.id.uuidString
         self.surfaceTree = controller.surfaceTree
+        self.effectiveFullscreenMode = controller.effectiveFullscreenMode
     }
 
     init?(coder aDecoder: NSCoder) {
@@ -28,6 +30,7 @@ class TerminalRestorableState: Codable {
 
         self.surfaceTree = v.value.surfaceTree
         self.focusedSurface = v.value.focusedSurface
+        self.effectiveFullscreenMode = v.value.effectiveFullscreenMode
     }
 
     func encode(with coder: NSCoder) {
@@ -109,11 +112,7 @@ class TerminalWindowRestoration: NSObject, NSWindowRestoration {
         }
 
         completionHandler(window, nil)
-        // We don't restore the previous fullscreen mode. If the saved mode differs from
-        // the current configuration, using either could be confusing. Instead, we honor
-        // the configured mode (consistent with new_window behavior).
-        let mode = appDelegate.ghostty.config.windowFullscreenMode
-        guard mode != .native else {
+        guard let mode = state.effectiveFullscreenMode, mode != .native else {
             // We let AppKit handle native fullscreen
             return
         }

macos/Sources/Helpers/Fullscreen.swift

@@ -2,7 +2,7 @@ import Cocoa
 import GhosttyKit
 
 /// The fullscreen modes we support define how the fullscreen behaves.
-enum FullscreenMode {
+enum FullscreenMode: String, Codable {
     case native
     case nonNative
     case nonNativeVisibleMenu