fix(grove): fix Korean Hangul IME composition with Shift in terminal

[DongGukMon]

Summary

• Fix Korean display in terminal on systems with malformed locale (bare UTF-8 rejected, tmux -u flag added, LANG/LC_CTYPE propagated)
• Fix Shift breaking Korean IME composition in terminal — characters requiring Shift (ㅆ, ㅖ, ㅃ, etc.) were impossible to type

Root cause

The xterm.js WKWebView patch (xtermjs/xterm.js#5704, not yet merged upstream) flushes pending IME composition on any non-229 keydown in _keyDown:

this._wkImeComposing && e.keyCode !== 229 && this._wkFlush(true)

This includes modifier keys (Shift=16, Ctrl=17, Alt=18, etc.), which prematurely sends the composing text to the PTY and breaks composition for Shift-required Korean characters.

Fix

Add modifier key exceptions to the _wkFlush guard in both xterm.js and xterm.mjs entry points:

this._wkImeComposing && e.keyCode !== 229
  && e.keyCode !== 16   // Shift
  && e.keyCode !== 17   // Ctrl
  && e.keyCode !== 18   // Alt
  && e.keyCode !== 20   // CapsLock
  && e.keyCode !== 91   // Left Meta
  && e.keyCode !== 93   // Right Meta
  && this._wkFlush(true)

Changed files

• grove/grove-core/src/pty.rs — locale fix + tmux UTF-8 flags
• grove/patches/@xterm__xterm.patch — modifier key exception in xterm.js WK IME flush
• grove/pnpm-lock.yaml — patch hash update

Test plan

• Type Korean characters requiring Shift (ㅆ, ㅖ, ㅃ, ㅉ, ㄸ) in grove terminal — composition should not break
• Type normal Korean characters (ㅅ, ㅏ, ㅇ) — should work as before
• Verify pnpm install && pnpm tauri dev builds and runs correctly