feat(tasks): infer bash task topics from folder structure

[Ajpantuso]

Summary

Closes #1269

These changes make it possible to define bash tasks in a nested folder structure under the predefined task directories. Tasks defined in directories below the parent tasks directory will have implied scope in their names by joining their relative path with :s.

For example a task defined at {{config_root}}/.mise/tasks/a/b/task will have task name a:b:task.

Additional Notes

• While walkdir was already a transitive dependency it is now a direct dependency to provide recursive walks through the filesystem.
• If a bash script task contains the : character it will be replaced by _ to prevent name collisions.
• Simple enough to test locally so I did, but some integration/e2e tests wouldn't hurt here.

[jdx]

incredible! Your rust is excellent btw, have you been writing it long?

[Ajpantuso]

incredible! Your rust is excellent btw, have you been writing it long?

Thanks, only about a year now, but I spent a good amount of time with Haskell in college so iterators/function composition/Algebraic Data Types are a little more natural for me now.