fix(chat-ui): stop hiding prose between dollar signs behind a math chip

[tkohout]

Description

The chat transcript parser in @emdash/chat-ui runs remark-math with single-dollar inline math enabled. Any prose between two $ signs (for example a sentence with two prices, "a $580 fee … pays $685") was parsed as a LaTeX expression and then replaced with a static ∑ math mention pill. The pill has no click handler or tooltip, so the text between the dollar signs was simply lost.

Changes:

• Disable single-dollar math in the chat-ui remark pipeline (singleDollarTextMath: false). Only $$…$$ is treated as math, which matches GitHub and most chat renderers.
• Render inline $$…$$ math as an inline code run containing the LaTeX source instead of the placeholder chip, so nothing is hidden. Block math already rendered its source as a paragraph and is unchanged.
• Update the stale tone comments in document.ts and mdast-mention.ts that referred to the math chip.

Not in scope: real KaTeX typesetting in the transcript. The chat renderer pre-measures prose with pretext and has no DOM access at layout time, so inline typesetting needs a separate design. Backslash delimiters (\(…\), \[…\]) are also untouched; they are not recognized as math and markdown escaping strips the backslash, as before.

Related issues

None.

Testing

• pnpm exec vitest run src/core/markdown/parse.test.ts in packages/chat-ui (35 passed, including two new cases: two dollar amounts survive verbatim; $$E = mc^2$$ becomes an inline code run).
• pnpm run typecheck in packages/chat-ui.
• pnpm exec oxlint packages/chat-ui/src/core/markdown and pnpm run format.
• Manual: dev app on an isolated profile, ACP chat conversation, agent asked to echo a sentence with five dollar amounts and a set of math examples. Verified the rendered transcript before and after with the same message.

Screenshot/Recording (if applicable)

Same assistant message rendered before and after.

Before: every $…$ and $$…$$ span collapses to the chip and the text between the two prices is gone.

After: prices and single-dollar text stay literal, $$ inline math shows its source as inline code.

Checklist

• I kept this PR small and focused
• I ran a self-review before opening this PR
• I ran the relevant local checks or explained why not
• I updated docs when behavior or setup changed
• I added or updated tests when behavior changed, or explained why not
• I only added comments where the logic is not obvious
• I used Conventional Commits for commit
  messages and, when possible, the PR title

🤖 Generated with Claude Code

[greptile-apps]

Confidence Score: 4/5

The PR appears safe to merge, with a non-blocking layout issue for inline math expressions wider than the transcript column.

Findings

1.  Long math expressions overflow ▶

Prompt To Fix All With AI

### Issue 1
packages/chat-ui/src/core/markdown/parse.ts:188
Rendering inline `$$…$$` as one code run makes long LaTeX expressions non-wrapping. Code runs use `break: 'never'` and `whiteSpace: 'pre'` inside a container with visible overflow, so an expression wider than the transcript column spills outside it. This is a non-blocking layout concern, but the source needs a bounded or wrapping presentation because the previous fixed-width `∑ math` chip could not cause this overflow.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

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For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Summary

• Configures remark-math to recognize only multi-dollar inline math.
• Converts inline math nodes into source-preserving code runs.
• Adds focused coverage for dollar-denominated prose and inline $$…$$ expressions.
• Updates mention documentation to remove obsolete math-chip references.
• Long inline expressions can now overflow because code runs are non-wrapping.

[greptile-apps]

Long math expressions overflow

Rendering inline $$…$$ as one code run makes long LaTeX expressions non-wrapping. Code runs use break: 'never' and whiteSpace: 'pre' inside a container with visible overflow, so an expression wider than the transcript column spills outside it. This is a non-blocking layout concern, but the source needs a bounded or wrapping presentation because the previous fixed-width ∑ math chip could not cause this overflow.

Prompt To Fix With AI

This is a comment left during a code review.
Path: packages/chat-ui/src/core/markdown/parse.ts
Line: 188

Comment:
**Long math expressions overflow**

Rendering inline `$$…$$` as one code run makes long LaTeX expressions non-wrapping. Code runs use `break: 'never'` and `whiteSpace: 'pre'` inside a container with visible overflow, so an expression wider than the transcript column spills outside it. This is a non-blocking layout concern, but the source needs a bounded or wrapping presentation because the previous fixed-width `∑ math` chip could not cause this overflow.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!