jnsgruk/agendrr ? reverse-engineered prompt

Build me a small Rust command line tool that reads events from Google Calendar and generates a markdown summary for a day, mainly so I can drop it into my Obsidian daily notes.

It should let me choose which day to fetch with an offset, read a config file for my calendar ID, email, preferred name, and optional rules for things like ignoring certain events, stripping suffixes from titles, and mapping long event names to note names. It should also support Google OAuth with a local credentials file, and save the token so I do not have to log in every time.

I want a debug mode that shows useful info, and I want the output to be clean markdown that links to the right notes. If you need to check current Google Calendar or Rust docs while wiring it up, go ahead. Please also include a simple example config and make it work nicely from the command line.