Fix autocomplete not triggering on mobile (CM5 input handling)

[aashu2006]

Issue:

Fixes #4007

This PR builds on the issue identified and discussed by @skyash-dev and me at Discord. We focused on investigating the mobile input behavior in CodeMirror and then I implementing a fix for the autocomplete trigger.

Autocomplete suggestions were not triggering reliably on mobile devices due to differences in CodeMirror’s input handling (IME + contenteditable path in CM5)

Demo:

Tested on a real Android device (Chrome). Autocomplete now appears while typing with the virtual keyboard.

Changes:

• Added mobile compatible autocomplete triggering using:
  • change (desktop input)
  • compositionend (word commit on mobile)
  • compositionupdate (IME typing support)
• Introduced triggerHint helper to unify logic
• Handled trailing spaces e.g. "bac " to ensure correct token detection
• Cleaned up debug code and simplified the logic

Notes:

• This PR focuses on fixing the autocomplete trigger issue on mobile (CM5).
• Keyboard focus behavior (virtual keyboard closing on suggestions) is not addressed here and I am thinking of handling it separately from this.

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• has no typecheck errors (npm run typecheck)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123
• meets the standards outlined in the accessibility guidelines

[aashu2006]

@raclim would appreciate your thoughts here as well, especially since this relates to the earlier discussion around mobile autocomplete behavior, thanks!