Use ActionView::TemplateDetails for handling format and variant

[sfnelson]

What are you trying to accomplish?

This change introduces ActionView::TemplateDetails as the primary abstraction for parsing and interpreting formats and variants. In a future PR I'll use this to implement template ordering based on the same logic that Rails uses for tie-breaks.

Discussion in #2128

What approach did you choose and why?

Rails already has complex and well-used logic for parsing template file names. ViewComponent's differences do not seem intentional, and using the Rails logic should make it easier for ViewComponents to avoid inconsistencies in the future.

I've split up the logic for the three different template types into separate classes. This helps reduce the conditional logic by using polymorphism instead. I've taken small steps and avoided any structural changes, but this lays the groundwork for more significant changes to the compiler logic.

Anything you want to highlight for special attention from reviewers?

I have broken compatibility with the previously supported variant.name feature. Rails explicitly does not allow period characters in variant names.

[joelhawksley]

Thanks for taking this on! I'll take a closer look once rebased ❤️

[sfnelson]

@joelhawksley thanks, I've rebased and removed the unnecessary change to format in Compiler. I've left the change in Template because it was already exposed as format and it's consistent with the change I've made to caching on my WIP branch.

[sfnelson]

@joelhawksley I think this code is ready for review. I'd think about this as a relatively minor internal refactor to ViewComponents that largely preserves compatibility at an API level – with the exception of dropping support for variants containing ..

I've run the benchmarks on my local dev machine and the results for this change are well within the margin of error vs V4. Attached if you're interested.

I have a second, larger branch ready to review but it's based on using Rails' TemplateDetails structure for describing format and variants, so I'd like to get this change merged first, if that's ok. I'll open a WIP PR that depends on this one.

v4.benchmark.txt
template-details.benchmark.txt

[joelhawksley]

I think this is great! Thank you so much for your contribution ❤️

[sfnelson]

Note, tests are failing due to Ruby 3.3.6 release