Add template lifecycle management

[irod973]

It'd be nice to be able to update projects that use this template after they've already been initialized. For example, if we have an update to ruff settings in pyproject.toml, I'd like to be able to push it to all downstream projects.

Some options:

Cruft. This would integrate nicely with the existing cookiecutter template. One concern is the waning maintenance. Last release was Dec 2024 and issue 312 explicitly asking about maintenance status was essentially non-comittal.

Copier looks much more modern and well maintained. However it doesn't seem to build on top of cookiecutter so this template repo would need to be migrated to copier scaffolding.

[reneleonhardt]

https://github.com/allenporter/scruft seems to be a maintained fork, but I can't see if it has been regularly synced with upstream 😄

[irod973]

@reneleonhardt Thanks for the suggestion! I think I got a custom solution working with some agentic coding in #5. It's not the most elegant solution but has worked thus far.

[reneleonhardt]

Great to see a first solution!

I hope 1,342 lines of custom code can be easily maintained 😄