RTL Support on macOS

[bo2themax]

Discussed in #9750

This is a tracking issue for right-to-left (RTL) language support on macOS. RTL languages — such as Arabic, Hebrew, and Persian — require the UI layout direction to be mirrored, with content flowing from right to left. macOS handles this system-wide when an RTL language is set as the primary language, but Ghostty currently does not fully respect this layout direction.

Native macOS apps (e.g. Terminal.app, Safari, Finder) adapt automatically. Ghostty does not yet do so consistently.

This parent issue tracks all RTL-related layout and rendering bugs on macOS. Known sub-issues:

How to Reproduce (General)

1. Product → Scheme → Edit Scheme → Run → Options
2. Set App Language to: Right-to-Left Pseudolanguage
   This is a built-in Xcode pseudo-language — no need to add Arabic/Hebrew as a real localization.
3. Open Ghostty and observe layout issues

Expected Behavior

All Ghostty UI chrome on macOS should correctly mirror its layout direction when the system is running in RTL mode, consistent with the behavior of native macOS applications.

References

• Apple HIG — Right to Left
• NSUserInterfaceLayoutDirection
• NSApp.userInterfaceLayoutDirection