Focus PTYTerminal on creation from ShellV2 menu

[Copilot]

Clicking the PTY menu option in ShellV2 creates the terminal tab but leaves keyboard focus on the HeadlessUI Menu button. The terminal only received focus later when the WebSocket onopen fired—if at all, since HeadlessUI's focus restoration could race against it.

• Added a deferred term.focus() immediately after term.open() in PtyTerminal's mount effect, matching the pattern already used by handleNewPortal for the same HeadlessUI focus-restoration issue

term.open(termRef.current);
fitAddon.fit();
termInstance.current = term;

// Deferred so HeadlessUI menu finishes restoring focus first.
setTimeout(() => term.focus(), 0);