[Bug]: Preserve native spellcheck behavior in the composer

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/web and apps/desktop

Steps to reproduce

1. Open a thread draft and type multiple misspelled words in the composer, for example speeling and teh.
2. Accept the native spelling correction for the first word from the host context menu.
3. Continue editing or right-click another underlined word.
4. On macOS desktop, also try a misspelling such as teting for which NSSpellChecker has suggestions.

Expected behavior

Accepting a correction should preserve the remaining native spelling markers and immediately re-check the edited text. The desktop context menu should show the operating system's available suggestions.

Actual behavior

Lexical's controlled replacement and full text-node reconciliation can make Blink discard existing spelling markers until the next real keystroke. Electron can also report an underlined misspelledWord with an empty dictionarySuggestions array even though the macOS checker has candidates, leaving the menu at No suggestions.

Impact

Minor bug or occasional failure

Version or commit

main at 6f34ad3e87eb

Environment

macOS 26.5.2; Electron 41.5.0; Chromium/Blink composer

Logs or stack traces

No runtime errors are emitted. For teting, macOS NSSpellChecker returns texting, testing, toting, teeing, and tenting while Chromium may provide no Electron dictionary suggestions.

Workaround

Typing another character can make the browser re-check the text. There is no consistent workaround for an empty desktop suggestion list.

Start by reproducing the composer behavior in apps/web and apps/desktop with multiple misspellings, accepting the first native correction, and opening the desktop context menu. Compare the remaining spelling markers and macOS suggestions with the Chromium/Electron results. Done means corrections preserve other native markers, edited text is rechecked immediately, and the desktop menu shows available operating-system suggestions.