macos: add focus and close AppleScript commands for terminals

Add two new AppleScript commands to the scripting dictionary:

- `focus terminal <terminal>` — focuses the given terminal and brings
  its window to the front.
- `close terminal <terminal>` — closes the given terminal without a
  confirmation prompt.

Each command is implemented as an NSScriptCommand subclass following
the same pattern as the existing split command.

macos/Sources/Features/AppleScript/ScriptFocusCommand.swift

@@ -0,0 +1,33 @@
+import AppKit
+
+/// Handler for the `focus` AppleScript command defined in `Ghostty.sdef`.
+///
+/// Cocoa scripting instantiates this class because the command's `<cocoa>` element
+/// specifies `class="GhosttyScriptFocusCommand"`. The runtime calls
+/// `performDefaultImplementation()` to execute the command.
+@MainActor
+@objc(GhosttyScriptFocusCommand)
+final class ScriptFocusCommand: NSScriptCommand {
+    override func performDefaultImplementation() -> Any? {
+        guard let terminal = evaluatedArguments?["terminal"] as? ScriptTerminal else {
+            scriptErrorNumber = errAEParamMissed
+            scriptErrorString = "Missing terminal target."
+            return nil
+        }
+
+        guard let surfaceView = terminal.surfaceView else {
+            scriptErrorNumber = errAEEventFailed
+            scriptErrorString = "Terminal surface is no longer available."
+            return nil
+        }
+
+        guard let controller = surfaceView.window?.windowController as? BaseTerminalController else {
+            scriptErrorNumber = errAEEventFailed
+            scriptErrorString = "Terminal is not in a window."
+            return nil
+        }
+
+        controller.focusSurface(surfaceView)
+        return nil
+    }
+}