fix: block typing over the divider block

[dielduarte]

Description

This PR adds a new ProseMirror plugin to the divider extension that blocks any transactions adding content (like type) over the divider.

I also had to update the bubble trigger to stop appearing in this case, so by default it's now the button and divider, but the user can override it by passing the prop hideWhenActiveNodes as before.

Video showing it working:
https://www.loom.com/share/cf524b2cba48449b91931fdf5532dc4e

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Summary by cubic

Blocks typing over the divider (horizontalRule) and hides the bubble menu when it’s selected to prevent accidental edits. Addresses Linear DEV-632.

• Bug Fixes
  • Added a ProseMirror plugin in the divider extension that blocks insert/replace when a horizontalRule is node-selected; Backspace still deletes it.
  • Updated bubble menu triggers to check NodeSelection; the menu hides when horizontalRule is selected.
  • Set default BubbleMenu hideWhenActiveNodes to ['button', 'horizontalRule'].
  • Added tests to ensure typing doesn’t replace the divider and Backspace deletes it.

^{Written for commit 4346632. Summary will update on new commits.}

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Project	Deployment	Actions	Updated (UTC)
react-email	Ready	Preview, Comment	May 13, 2026 4:51pm
react-email-demo	Ready	Preview, Comment	May 13, 2026 4:51pm

[changeset-bot]

🦋 Changeset detected

Latest commit: 4346632

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@react-email/editor	Patch

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commit: 4346632

[cubic-dev-ai]

cubic analysis

No issues found across 5 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

Linked issue analysis

Linked issue: DEV-632: It's possible to just type over the divider

Status	Acceptance criteria	Notes
✅	Prevent transactions that insert content (typing) from replacing a horizontal rule when the divider is node-selected	A ProseMirror plugin was added that filters transactions when the selection is a NodeSelection on a 'horizontalRule' and rejects ReplaceStep instances that insert content. Tests were added asserting typing does not replace the divider.
✅	Hide the bubble menu by default when the divider (horizontalRule) is active/selected (while preserving the ability to override via hideWhenActiveNodes)	The bubble-menu trigger now returns false when the current selection is a NodeSelection whose node type is included in hideWhenActiveNodes. The default hideWhenActiveNodes was updated to include 'horizontalRule' in both the example and EmailEditor, preserving the prop override behavior.

_{Auto-approved: This PR adds a ProseMirror plugin to block typing over the divider while still allowing deletion, with updated bubble menu defaults and tests, all within the email editor's isolated extension system.}