fix(web): inline styles inheritance in newline

[kacperzolkiewski]

Summary

After tiptap upgrade: #655 when adding a newline inside e.g. bolded text caused that in newline inline style was wrongly inactive.

This PR fixes that behaviour.

Test Plan

1. Toggle bold
2. Type "Hello world"
3. Go with the cursor in the middle of typed text
4. press enter
5. Type "hello"

Bold should still be active and text in second line should be bolded.

Screenshots / Videos

before:

Screen.Recording.2026-06-29.at.08.19.29.mov

after:

Screen.Recording.2026-06-29.at.08.18.24.mov

Compatibility

OS	Implemented
iOS	❌
Android	❌
Web	✅

Checklist

• E2E tests are passing
• Required E2E tests have been added (if applicable)

[Copilot]

Pull request overview

Fixes a regression after the Tiptap upgrade where pressing Enter inside inline-styled text could incorrectly deactivate the active inline mark for the new line (e.g., bold not being inherited).

Changes:

• Update StrictMarksPlugin to only run its strict-mark reconciliation when the document or selection actually changes.
• Add a Playwright E2E regression test covering Enter-in-the-middle-of-bold-followed-by-plain-text, ensuring bold remains active and typed text is bold.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/web/pmPlugins/StrictMarksPlugin.ts	Avoids running strict-mark reconciliation on transactions that don’t change doc/selection, preventing incorrect stored-mark resets after Enter.
.playwright/tests/strictMarks.spec.ts	Adds an E2E regression test validating bold inheritance/activation when inserting a newline mid-bold before plain text.

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