Bold formatting not split at emoji boundaries causing duplicate text on web

[TaduJR]

Problem

When combining bold formatting with emojis (e.g., *bold 😀 text*), the web platform displays duplicate emoji characters. This also causes cursor positioning issues.

Steps to Reproduce

1. Open the web app
2. In the chat composer, type: *bold 😀 text*
3. Observe duplicate emoji in the rendered output