[codex] fix iOS WebKit markdown autolink bundle

[chaochaoweb3]

Summary

• replace browser-bundled remark-gfm with a local GFM preset that excludes gfm-autolink-literal
• keep GFM footnotes, strikethrough, tables, and task-list items enabled for default and classic frontends
• alias third-party remark-gfm imports, including Streamdown, to the compatible preset during Rsbuild bundling

Why

mdast-util-gfm-autolink-literal@2.0.1 includes an email autolink regex with lookbehind syntax. iOS 16.1 WebKit cannot parse that regex, so any bundle containing it can fail before React mounts.

Validation

• cd web && npm exec --yes --package=bun -- bun install --frozen-lockfile
• cd web/default && npm exec --yes --package=bun -- bun run typecheck
• cd web/default && npm exec --yes --package=bun -- bun run build
• rg --fixed-strings "(?<=^|\\s|\\p{P}|\\p{S})" web/default/dist web/default/src web/classic/src web/default/rsbuild.config.ts web/classic/rsbuild.config.ts returned no matches
• rg "gfmAutolinkLiteral|literalAutolinkEmail|mdast-util-gfm-autolink-literal" web/default/dist web/default/src web/classic/src web/default/rsbuild.config.ts web/classic/rsbuild.config.ts returned no matches
• git diff --check

Note: web/classic build currently fails on main because date-fns-tz@1.3.8 resolves against date-fns@4 exports, tracked separately in #5670 with an existing fix PR #5676. This PR intentionally does not duplicate that unrelated dependency fix.

Fixes #5550

Summary by CodeRabbit

• New Features
  • Markdown rendering now supports more GitHub-flavored formatting, including footnotes, strikethrough, tables, and task lists.
  • Improved compatibility for these markdown features across the app’s classic web experience.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: d883090f-ffaf-4a0b-aed9-7e985869f960

📥 Commits

Reviewing files that changed from the base of the PR and between bf17259 and 75cdac4.

⛔ Files ignored due to path filters (1)

• web/bun.lock is excluded by !**/*.lock

📒 Files selected for processing (4)

• web/classic/package.json
• web/classic/rsbuild.config.ts
• web/classic/src/components/common/markdown/MarkdownRenderer.jsx
• web/classic/src/helpers/remarkGfmCompatible.js

✅ Files skipped from review due to trivial changes (1)

• web/classic/rsbuild.config.ts

🚧 Files skipped from review as they are similar to previous changes (3)

• web/classic/src/helpers/remarkGfmCompatible.js
• web/classic/package.json
• web/classic/src/components/common/markdown/MarkdownRenderer.jsx

---

Walkthrough

Adds a local remarkGfmCompatible.js helper to web/classic that manually registers GFM micromark and mdast extensions for footnotes, strikethrough, tables, and task lists—intentionally excluding mdast-util-gfm-autolink-literal. The build config aliases remark-gfm to this local module, and MarkdownRenderer.jsx is updated to use it. Eight new GFM sub-packages are added as explicit dependencies.

WebKit-compatible GFM plugin for web/classic

Layer / File(s)	Summary
Compatible GFM plugin implementation and dependencies web/classic/package.json, web/classic/src/helpers/remarkGfmCompatible.js	Eight mdast-util-gfm-* and micromark-extension-gfm-* sub-packages added as dependencies. New remarkGfmCompatible function registers micromark/mdast extensions for footnotes, strikethrough, tables, and task lists, omitting the autolink-literal module that contains the problematic lookbehind RegExp.
Build alias and component integration web/classic/rsbuild.config.ts, web/classic/src/components/common/markdown/MarkdownRenderer.jsx	rsbuild.config.ts aliases remark-gfm to the local helper. MarkdownRenderer.jsx imports RemarkGfmCompatible and uses it in the ReactMarkdown remarkPlugins array.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐇 A lookbehind lurked in the bundle so deep,
Crashing old WebKit and breaking its sleep.
I hopped past the autolink, crafted my own,
Now footnotes and tables are safely at home.
iOS 16.1 can browse without fright — ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly states the iOS WebKit markdown/autolink fix and matches the main change.
Linked Issues check	✅ Passed	The changes replace remark-gfm with a local compatible preset that omits autolink lookbehind while preserving other GFM features.
Out of Scope Changes check	✅ Passed	All edits support the WebKit compatibility fix; no unrelated code paths or features were introduced.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[chaochaoweb3]

Rebased this PR onto the latest main and resolved the conflicts.

The default frontend has since moved away from the react-markdown / remark-gfm path to the newer marked renderer, so I dropped the now-obsolete default-frontend compatibility alias and helper from this PR. The remaining change is scoped to the classic frontend, which still imports remark-gfm via react-markdown.

Validation run locally:

• git diff --check upstream/main...HEAD

I could not run the Bun workspace build here because this machine does not currently have bun installed.