fix(markdown): render file previews statically

[PeppaPigw]

What

Render file-backed Markdown previews in static mode instead of Streamdown's streaming/incomplete-repair path. Add a regression test to lock the preview configuration.

Why

Opening a 7,646-line Markdown note made the entire app sluggish after the preview loaded, not just the preview pane. The preview path was treating a complete file like streaming AI output, doing extra incomplete-markdown repair work and leaving an expensive rendered tab mounted.

Local benchmark on the same Markdown content:

Path	Wall time	CPU time
Streaming repair path	3,295 ms	4,083 ms
Static file-preview path	476 ms	801 ms

The reduced CPU/main-thread rendering work matches the manual result: after the fix, opening the large Markdown file no longer makes the rest of the app feel stuck.

How

Only the rendered Markdown file preview path changed: MarkdownPreviewPane now passes mode="static" and parseIncompleteMarkdown={false} to Streamdown. AI chat rendering still uses the existing streaming behavior.

Testing

• pnpm test src/modules/markdown/MarkdownPreviewPane.test.ts
• pnpm check-types
• pnpm exec biome lint src/modules/markdown/MarkdownPreviewPane.tsx src/modules/markdown/MarkdownPreviewPane.test.ts
• Manual smoke-test affected feature in pnpm tauri dev
• Platforms tested: local dev on Linux workspace

Notes reviewer

This is intentionally narrow: only the rendered Markdown file preview changed. AGENTS.generated.md was left untracked and not committed.

[coderabbitai]

📝 Walkthrough

Walkthrough

Two new props, mode="static" and parseIncompleteMarkdown={false}, were added to the Streamdown component in MarkdownPreviewPane.tsx, altering its markdown parsing/rendering behavior. A new test file was added to verify these configuration values via source extraction.

Changes

Markdown Preview Rendering Configuration

Layer / File(s)	Summary
Streamdown static mode props and test src/modules/markdown/MarkdownPreviewPane.tsx, src/modules/markdown/MarkdownPreviewPane.test.ts	Streamdown now renders with mode="static" and parseIncompleteMarkdown={false}; a new test reads the component source and asserts these two prop values are present.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Related PRs: None identified.

Suggested labels: markdown, tests

Suggested reviewers: None identified.

No secret sauce needed here — flipping Streamdown to static mode and turning off incomplete-markdown repair is a two-line change, and the test cleverly regex-scrapes the source to keep it honest. Bundle size, RAM, and terminal-first ethos: unaffected. My only nudge — the regex-based test is a bit brittle to formatting changes in the JSX, but for a two-prop guardrail, it's fine. Ship it.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title follows Conventional Commits and accurately summarizes the main change to static Markdown file previews.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}