fix(editor): avoid copying paraId on split

[wookieb]

Summary

• Prevent paragraph splits from carrying over DOCX paraId identity.
• Avoid duplicate block IDs after pressing Enter in table separator paragraphs.

Closes #3405

Considerations

Regular splitRunToParagraph does not copy paraId on purpose. Split on empty paragraph is special, therefore I believe the best fix is to just mark attribute as ignored on split.

I was thinking about not having paraId at for table separator but I've noticed it was added on purpose in recent months. Unless... I'm wrong?

[caio-pizzol]

@wookieb thanks for the PR. this matches the editor split path, and the regression test covers the reported duplicate paraId case. lgtm once the inline is handled.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[gpardhivvarma]

after this + the textId change land, three sites will be nulling paraId/textId on split — keepOnSplit: false here, the spread in split-run.js:97-105, and the deletes in tables-adapter.ts:2119-2122. easy to update one and miss the others. worth routing splitBlockPatch through Attribute.getSplittedAttributes so this file is the only declaration site? rough sketch:

// split-run.js, replacing the spread at 97-105
const extensionAttrs = editor?.extensionService?.attributes ?? [];
paragraphAttrs = Attribute.getSplittedAttributes(extensionAttrs, node.type.name, node.attrs);

one wrinkle: getSplittedAttributes would also drop listRendering (also keepOnSplit: false), which the hand-rolled spread currently preserves — not sure if that's intentional.

[wookieb]

That was a good tip @gpardhivvarma - Thank You :)