Add scripting dictionary commands for activating windows, selecting tabs,
closing tabs, and closing windows.
Implement the corresponding Cocoa AppleScript command handlers and expose
minimal ScriptWindow/ScriptTab helpers needed to resolve live targets.
Verified by building Ghostty and running osascript commands against the
absolute Debug app path to exercise all four new commands.
Add a `name` property (code `pnam`, cocoa key `title`) to the window, tab,
and terminal classes in the scripting definition. This follows the standard
Cocoa scripting convention where `name`/`pnam` maps to the `title` KVC key,
matching what Apple does in CocoaStandard.sdef for NSWindow.
Also fixes the pre-existing terminal `title` property which used a custom
four-char code (`Gttl`) that AppleScript could not resolve directly — only
via `properties of terminal`. All three classes now use the standard `pnam`
code so `name of window 1`, `name of tab 1 of window 1`, and
`name of terminal 1` all work correctly.
Expose terminal surfaces as elements on both ScriptWindow and ScriptTab,
allowing AppleScript to enumerate terminals scoped to a specific window
or tab (e.g. `terminals of window 1`, `terminals of tab 1 of window 1`).
Changes:
- Add `<element type="terminal">` to window and tab classes in Ghostty.sdef
- Add `terminals` computed property and `valueInTerminalsWithUniqueID:`
lookup to ScriptWindow (returns all surfaces across all tabs)
- Add `terminals` computed property and `valueInTerminalsWithUniqueID:`
lookup to ScriptTab (returns surfaces within that tab)
