fix: keep the editor styled when editorClassName prop changes

[maccman]

Problem

ProseKitEditor renders the element ProseMirror mounts into as:

<div ref={editor.mount} className={clsx('meowdown-content', editorClassName)} />

ProseMirror puts ProseMirror — and ProseMirror-focused while focused — on that
same element itself, via classList, so it composes with whatever else is there.
React's className prop is a whole-attribute write, so any re-render with a
changed editorClassName wipes ProseMirror's tokens, and they are not restored:
PM's own bookkeeping still believes they are applied. Every .ProseMirror … rule
in the stylesheet stops matching until the editor remounts.

The most visible symptom is a wikilink's raw source appearing next to its label —
.ProseMirror .md-atom-view-content { font-size: 0; opacity: 0 } is the only thing
hiding it:

Meetings
• 12:00pm met with Alice Wyatt[[Alice Wyatt]] for lunch

It reads like "live preview turned itself off", but the document is fine; only the
class is gone. .ProseMirror-focused goes the same way, which drops the virtual
caret's focused styling.

This is easy to hit from a host that sizes the editor from state. In Reflect, each
daily-stream row passes min-h-[60vh] for today and min-h-[100px] for past days;
when local midnight passes with the app open, yesterday's row re-renders with the
new class and loses its styling until it is scrolled out of the virtualizer and back.

Fix

Apply the host's classes imperatively, token by token, so both writers stay
additive — only classes Meowdown applied itself are ever removed. React no longer
sets className on that element at all.

MarkdownView is unaffected: it renders its own static tree with no ProseMirror
view, and already includes ProseMirror in its class list.

Testing

• Two regression tests in editor.test.tsx: the class list survives an
  editorClassName change, and a wikilink's source stays at font-size: 0px
  across one. Both fail on master (they time out waiting for the class) and
  pass here.
• pnpm typecheck, oxfmt --check and eslint clean on the changed files.
• Full @meowdown/react suite: 279 passed in Chromium; editor +
  prosekit-editor also run green under MEOWDOWN_TEST_BROWSER=webkit.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated (UTC)
meowdown	Ready	Preview	Jul 25, 2026 6:57pm

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commit: 2df302d

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	93.13%	4423 / 4749
🔵	Statements	90.81%	4966 / 5468
🔵	Functions	90.77%	1073 / 1182
🔵	Branches	86.54%	3189 / 3685

File Coverage

File	Stmts	Branches	Functions	Lines	Uncovered Lines
Changed Files
packages/core/src/index.ts	0%	0%	0%	0%
packages/core/src/extensions/extension.ts	100%	100%	100%	100%
packages/core/src/extensions/view-attributes.ts	100%	100%	100%	100%
packages/react/src/components/editor-extensions.tsx	100%	95%	100%	100%
packages/react/src/components/prosekit-editor.tsx	94.16%	89.77%	93.75%	97.16%	75, 91, 121, 132, 355, 427-430

Generated in workflow #1463 for commit 2df302d by the Vitest Coverage Report Action

[ocavue]

Thanks. Good catch. I've changed the implementation but kept your tests.