macos: add AppleScript commands for text input, key, and mouse events

Add five new AppleScript commands to Ghostty.sdef mirroring the existing
App Intents for terminal input:

- `input text`: send text to a terminal as if pasted
- `send key`: simulate a keyboard event with optional action and modifiers
- `send mouse button`: send a mouse button press/release event
- `send mouse position`: send a mouse cursor position event
- `send mouse scroll`: send a scroll event with precision and momentum

A shared `input action` enumeration (press/release) is used by both key
and mouse button commands. Modifier keys are passed as a comma-separated
string parameter (shift, control, option, command).

macos/Sources/Features/AppleScript/ScriptInputTextCommand.swift

@@ -0,0 +1,39 @@
+import AppKit
+
+/// Handler for the `input text` AppleScript command defined in `Ghostty.sdef`.
+///
+/// Cocoa scripting instantiates this class because the command's `<cocoa>` element
+/// specifies `class="GhosttyScriptInputTextCommand"`. The runtime calls
+/// `performDefaultImplementation()` to execute the command.
+@MainActor
+@objc(GhosttyScriptInputTextCommand)
+final class ScriptInputTextCommand: NSScriptCommand {
+    override func performDefaultImplementation() -> Any? {
+        guard let text = directParameter as? String else {
+            scriptErrorNumber = errAEParamMissed
+            scriptErrorString = "Missing text to input."
+            return nil
+        }
+
+        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 surface = surfaceView.surfaceModel else {
+            scriptErrorNumber = errAEEventFailed
+            scriptErrorString = "Terminal surface model is not available."
+            return nil
+        }
+
+        surface.sendText(text)
+        return nil
+    }
+}