Bots: some api to add extra metadata to message info

For developing bots it would be cool to have some way to add custom metadata to messages that can be viewed by users if you ask them for it, but is not as visible/present as an HTML part.

Does not need to be much, maybe just an extra encrypted header which contents are shown in the Message Details dialog/screen on the apps. Max size whatever a single encrypted header can hold.

Example use-cases:

  • to show the time a request took internally (like a internet search bot)
  • or for an LLM bot the tokens that were used in generating the bot’s reply.

Like metadata that can be interesting for some but not all users.

As long as Remade message details and show them in a friendly matter for non-technical users - #11 by Simon is not implemented yet, the implementation can be done fully in core without touching UI code.