Emoji Easy Entry

Either add an auto-replace like slack (and GitHub) where :emoji: becomes an emoji character or add a button where someone can select an emoji from the list. I think the colon syntax is for more advanced users where the button would be for more casual users so both would probably be helpful

The issue does not name files, tests, or an entry point. Start by locating the chat message composer and its current emoji handling, then determine whether both colon replacement and an emoji-selection button are required; done means users can enter emojis through the agreed interface without disrupting normal messages.

Written by the indexing model from the issue text.