feat: allow disabling chat message recording

[solaoi]

Summary

Adds a recording_settings.record_chat_messages option for disabling the recording of incoming meeting chat messages.

The option defaults to true to preserve existing behavior.

When set to false:

• Google Meet does not decode or forward incoming chat messages
• Microsoft Teams does not process or forward incoming chat events
• Zoom native bots do not register the incoming chat callback
• Incoming chat messages are not logged, stored, or sent through webhooks
• Bots can still send chat messages

Usage

{
  "recording_settings": {
    "record_chat_messages": false
  }
}

record_chat_messages: false takes precedence over record_chat_messages_when_paused.

Testing

• Added tests for the default-enabled behavior
• Added tests confirming incoming messages are not scheduled or stored when disabled
• Added a regression test confirming outgoing chat messages still work
• Added adapter-level checks for web bots and Zoom
• Ran the existing bot creation and recording settings tests

No database migration is required because the option is stored in the existing recording settings JSON.