macos: use direct parameters for object-targeting commands

Change split, focus, close, activate window, select tab, close tab, and
close window commands to accept their target object as a direct parameter
instead of a named parameter. This produces natural AppleScript syntax:

  activate window (window 1)
  close tab (tab 1 of window 1)
  split (terminal 1) direction right

instead of the awkward redundant form:

  activate window window (window 1)
  close tab tab (tab 1 of window 1)
  split terminal (terminal 1) direction right

The implementation moves command logic from NSScriptCommand subclasses
into responds-to handler methods on ScriptTerminal, ScriptWindow, and
ScriptTab, which is the standard Cocoa Scripting pattern for commands
whose direct parameter is an application class.

macos/Sources/Features/AppleScript/ScriptWindow.swift

@@ -174,6 +174,42 @@ final class ScriptWindow: NSObject {
         return controllers.first
     }
 
+    /// Handler for `activate window <window>`.
+    @objc(handleActivateWindowCommand:)
+    func handleActivateWindow(_ command: NSScriptCommand) -> Any? {
+        guard NSApp.validateScript(command: command) else { return nil }
+
+        guard let windowContainer = preferredParentWindow else {
+            command.scriptErrorNumber = errAEEventFailed
+            command.scriptErrorString = "Window is no longer available."
+            return nil
+        }
+
+        windowContainer.makeKeyAndOrderFront(nil)
+        NSApp.activate(ignoringOtherApps: true)
+        return nil
+    }
+
+    /// Handler for `close window <window>`.
+    @objc(handleCloseWindowCommand:)
+    func handleCloseWindow(_ command: NSScriptCommand) -> Any? {
+        guard NSApp.validateScript(command: command) else { return nil }
+
+        if let managedTerminalController = preferredController as? TerminalController {
+            managedTerminalController.closeWindowImmediately()
+            return nil
+        }
+
+        guard let windowContainer = preferredParentWindow else {
+            command.scriptErrorNumber = errAEEventFailed
+            command.scriptErrorString = "Window is no longer available."
+            return nil
+        }
+
+        windowContainer.close()
+        return nil
+    }
+
     /// Provides Cocoa scripting with a canonical "path" back to this object.
     ///
     /// Without this, Cocoa can return data but cannot reliably build object