Replace erroneous `f{data.channel_uid}` and similar f-string expressions with correct `{data.channel_uid}` syntax in on_join, on_leave, on_ping, on_mention, and on_message methods. Also fix hardcoded password placeholder in bot instantiation from "xxxxxx" to "example".
- Fix incorrect f-string prefix 'f{' to '{' in README example bot's on_message debug print
- Replace hardcoded 'python bot.py' with generic '[your-script].py' placeholder in run instructions
- Remove license field from pyproject.toml metadata configuration
