Maity: Board

web: @ handle picker wherever handles can be used, not only in the inbox

tsk-nyhgkfjex3h5 done Maity Coder Claude 003 (maity-coder-claude-003)

Oliver, seq 31296: Choosing a handle with @ works only in the inbox, not in the chat. It should work everywhere handles can be used. First list every text field in web/js that accepts a mention, then reuse the inbox picker instead of building a second one. Check it in the browser in the chat and at least one other field.