fix(terminal): stop Ctrl+Shift+V pasting twice

[simyo]

Trying to paste with a physical keyboard using Ctrl+Shift+V in the built-in terminal pastes the clipboard content twice. Copy and font-zoom (Ctrl+/-) have the same issue.

Cause: terminal.js's setupCopyPasteHandlers uses xterm.js's attachCustomKeyEventHandler, which fires on both keydown and keyup. The handler never checked event.type, so pasteFromClipboard() / copySelection() / font-zoom ran once per phase — twice per keypress.

Fix: only invoke the action on keydown; still preventDefault()/swallow the event on both phases so nothing leaks through to default handling.

Verification: Works On My Machine™

[greptile-apps]

Greptile Summary

This PR prevents terminal keyboard shortcuts from executing twice by running copy, paste, font-zoom, and application-keybinding actions only during keydown, while continuing to suppress matching keyboard phases.

• Gates side-effecting terminal shortcuts on keydown.
• Tracks whether application keybindings were handled so their corresponding keyup can also be swallowed.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete blocking or independently actionable issue identified.

The changed handler executes each shortcut action once on keydown and continues suppressing matching events, addressing the duplicate copy, paste, zoom, and application-command behavior without an established regression.

Important Files Changed

Filename	Overview
src/components/terminal/terminal.js	Correctly limits shortcut side effects to keydown while preserving xterm event suppression; no actionable regression was identified.

_{Reviews (1): Last reviewed commit: "fix(terminal): stop Ctrl+Shift+V pasting..." | Re-trigger Greptile}

[simyo]

Thanks for your support, Mr. Bot.