Typst is missing from the chat code-block language picker

What version of the Codex App are you using (From “About Codex” dialog)?

26.901.51231

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Darwin 25.6.0 arm64 arm

What issue are you seeing?

Typst is missing from the language picker for code blocks in Codex App chats. As a result, a chat code block cannot be explicitly set to Typst and does not receive Typst syntax highlighting.

What steps can reproduce the bug?

1. Open a chat in the Codex App.
2. Create or receive a fenced code block containing Typst source.
3. Open the code block's language picker.
4. Search for Typst or typst.

Typst is not listed.

Example:

#set page(width: 10cm)
= Hello, Codex

What is the expected behavior?

The language picker should offer Typst, and selecting it should apply Typst syntax highlighting to the code block.

Additional information

No matching open or closed issue was found by searching this repository for Typst syntax highlighting.

The packaged app already contains Shiki's Typst grammar, including the typ alias and .typ file mapping. However, the chat code-block path uses a separate hardcoded highlight.js language registry, and Typst is absent from that registry. This appears to explain why Shiki's existing Typst support does not reach the chat language picker.

Start at the chat code-block language picker and its separate hardcoded highlight.js language registry; verify how the packaged Shiki Typst grammar is unrelated to this path. Done means searching for Typst finds it in the picker, and selecting it applies Typst syntax highlighting to the provided fenced example.