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/ScriptMousePosCommand.swift

@@ -0,0 +1,63 @@
+import AppKit
+
+/// Handler for the `send mouse position` AppleScript command defined in `Ghostty.sdef`.
+///
+/// Cocoa scripting instantiates this class because the command's `<cocoa>` element
+/// specifies `class="GhosttyScriptMousePosCommand"`. The runtime calls
+/// `performDefaultImplementation()` to execute the command.
+@MainActor
+@objc(GhosttyScriptMousePosCommand)
+final class ScriptMousePosCommand: NSScriptCommand {
+    override func performDefaultImplementation() -> Any? {
+        guard let x = evaluatedArguments?["x"] as? Double else {
+            scriptErrorNumber = errAEParamMissed
+            scriptErrorString = "Missing x position."
+            return nil
+        }
+
+        guard let y = evaluatedArguments?["y"] as? Double else {
+            scriptErrorNumber = errAEParamMissed
+            scriptErrorString = "Missing y position."
+            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
+        }
+
+        let mods: Ghostty.Input.Mods
+        if let modsString = evaluatedArguments?["modifiers"] as? String {
+            guard let parsed = Ghostty.Input.Mods(scriptModifiers: modsString) else {
+                scriptErrorNumber = errAECoercionFail
+                scriptErrorString = "Unknown modifier in: \(modsString)"
+                return nil
+            }
+            mods = parsed
+        } else {
+            mods = []
+        }
+
+        let mousePosEvent = Ghostty.Input.MousePosEvent(
+            x: x,
+            y: y,
+            mods: mods
+        )
+        surface.sendMousePos(mousePosEvent)
+
+        return nil
+    }
+}