Support Slack-style emoji shortcodes in chat input

Feature Request

Support Slack-style emoji shortcodes (e.g. :thumbsup:, :rocket:, :fire:) in user input, converting them to their Unicode emoji equivalents before display.

Motivation

When chatting in Claude Code, typing :thumbsup: renders as the literal string :thumbsup: instead of 👍. Users coming from Slack, GitHub, Discord, and other tools expect shortcode-to-emoji conversion.

Suggested Behavior

• Convert known shortcodes to Unicode emoji on display (e.g. :thumbsup: → 👍)
• Support the standard shortcode set (GitHub/Slack compatible)
• Optionally: autocomplete shortcodes as the user types (:thu → suggestion dropdown)

Workaround

macOS users can use Cmd+Ctrl+Space to open the system emoji picker, but shortcode support would be faster for keyboard-heavy workflows.

🤖 Filed via Claude Code