Explore converting astrodb-bot to an Agent Plugin

See this video on agent plugins: https://youtu.be/Mnyc9gUTq7E?si=J18FVQ4em_exYhpk
And more details of the standard at https://agent-plugins.org/

We may be able to convert astrodb-bot to be a plugin which would make it much easier to set up and share.

Start by reviewing the agent plugin standard at agent-plugins.org and the linked video, then inspect how astrodb-bot is currently set up. Determine whether the existing bot can fit the standard, identify the required changes, and document a concrete conversion plan or working plugin shape as the definition of done.

Written by the indexing model from the issue text.