Vouch Request: RTL text shaping for Arabic and Hebrew

[DiaaEddin]

What do you want to change?

I'd like to add RTL shaping in the font shaping layer for Arabic to render correctly, as currently shaping is forced to LTR so words for arabic come out shaped but backward, completely unreadable.

the change is 4 files, all in font/shaper layer, It detects direction via uucode bidi_class, splits runs at LTR/RTL boundaries, and fix shaping.

terminal mode, selection, cursor, positioning are not gonna be touched for the first pr, as a first stage for supporting rtl. further changes are needed to meet the specs for rtl in terminal but these need to go in other layers.

Why do you want to make this change?

becuase currently text in arabic is appearing backward, even though shaper is used, but still completely unreadable. as I was checking #1740 and #1442 after being frustrated for while now, I really like ghostty and as a native arabic speak daily user working in UAE this is the only major drawback for my shift from terminal app on mac to ghostty.

AI disclosure: the pr is ready, already tested it myself manually , wrote the tests etc, I used claude code (opus 4.6) for implementation help/tests, codex gpt-codex-5.3 for code review.

I acknowledge that:

• I have read the Contributing Guide and understand the contribution process.
• I have read and agree to follow the AI Usage Policy.
• I wrote this vouch request myself, in my own voice, without AI generating it.

[jcollie]

!vouch