Add the context to the Swift layer.

- Define NewSurfaceContext to match the Zig enum name and avoid magic numbers.

macos/Sources/Ghostty/Surface View/SurfaceView.swift

@@ -625,6 +625,13 @@ extension Ghostty {
         #endif
     }
 
+    /// Context for surface creation, matching the Zig NewSurfaceContext enum
+    enum NewSurfaceContext: Int32 {
+        case window = 0
+        case tab = 1
+        case split = 2
+    }
+
     /// The configuration for a surface. For any configuration not set, defaults will be chosen from
     /// libghostty, usually from the Ghostty configuration.
     struct SurfaceConfiguration {
@@ -646,6 +653,9 @@ extension Ghostty {
         /// Wait after the command
         var waitAfterCommand: Bool = false
 
+        /// Context for surface creation
+        var context: NewSurfaceContext = .window
+
         init() {}
 
         init(from config: ghostty_surface_config_s) {
@@ -667,6 +677,7 @@ extension Ghostty {
                     }
                 }
             }
+            self.context = NewSurfaceContext(rawValue: config.context) ?? .window
         }
 
         /// Provides a C-compatible ghostty configuration within a closure. The configuration
@@ -700,6 +711,9 @@ extension Ghostty {
             // Set wait after command
             config.wait_after_command = waitAfterCommand
 
+            // Set context
+            config.context = context.rawValue
+
             // Use withCString to ensure strings remain valid for the duration of the closure
             return try workingDirectory.withCString { cWorkingDir in
                 config.working_directory = cWorkingDir