Cached recipe tracking issue

`just` now has a `[cache]` attribute added in #3437 and released in [1.54.0](https://github.com/casey/just/releases/tag/1.54.0) which skip recipe invocations if an entry matching the invocation is found in an on-disk cache.

This is a complex feature, so try it out and let me know what you think!

Possible future additions:
- Check input file mtime instead of hashing
- Invalidate cache if an executable changes
- Remove automatically added cache keys
- Allow input files to be directories
- Cache shell recipes
- Allow referencing `extra`, `inputs`, and `outputs` in recipe

Start by trying the `[cache]` attribute released in just 1.54.0 and exercise recipe invocations against an on-disk cache. Review the listed future additions and record concrete behavior gaps; done is a clearly scoped follow-up with reproducible observations.

Written by the indexing model from the issue text.