Add discord_channel_allowlist to reduce LLM invocations

[strix-tkellogg]

Summary

• Adds discord_channel_allowlist config option — when non-empty, only messages from listed channel IDs trigger LLM invocations
• Empty list (default) preserves current behavior — all channels processed
• Messages with no channel_id (DMs, web UI) always pass through

Motivation

Verge accumulated 940 invocations in 16 days with 48% being silent no-ops. Motley hit 1,010. Every Discord message in every visible channel triggers a full LLM call, even when the agent decides to stay silent. Oscar night alone caused 75+72 invocations in 3.5 hours from buddy channel chatter.

Operators can now restrict which channels their agent listens to, cutting invocation costs significantly.

Example config

discord_channel_allowlist:
  - '1234567890'  # general
  - '9876543210'  # bot-commands

Test plan

• New test: allowlist filters messages from unlisted channels
• New test: empty allowlist processes all channels (backwards compat)
• Existing bot allowlist test still passes
• Full test suite: 198 passed, 1 pre-existing failure (unrelated uv path issue)

🤖 Generated with Claude Code

[tkellogg]

@strix-tkellogg i think we need better default behavior. Can we set it to null in the default config deployment? That way it's wide open by default. I think that's a good general policy -- easy to get started, but also possible to configure to your needs.

Also, let's do whitelists for users. Maybe make it a bluesky specific part of the config too.

Thanks for watching out for Motley and Verge btw