refactor: unify tarball resolution and optimize download latency

[aprendendofelipe]

• Replace multiple specific endpoints with a global tarball-resolver middleware.
• Remove 302 redirects.
• Eliminate routing hacks required to prevent Nitro from hijacking Vue's / and /~/... routes.
• Improve E2E testability by introducing x-commit-key and x-pkg-name-key headers.
• Make analytics database writes non-blocking (event.waitUntil).

[aprendendofelipe]

Marking as draft. I need to fix a bug when ref is a branch name containing @. I'll check this out later.

[aprendendofelipe]

I updated the workflow_run.in_progress.json fixture to use a chaotic branch name (@test/@chaotic.branch/name-@v1.@) to stress-test the resolver. Interestingly, I noticed the current version of the service also fails to parse this payload correctly. This PR fixes that pre-existing bug!

[Aslemammad]

Amazing, does this have og:images? something brand friendly? maybe we can work on it in a different PR, which i'd love to see it in pkg.pr.new. also feel free to update the PR and fix the conflicts so it'd be mergable. really appreciate the effort.

but i'll get back to this PR after we make a release for #465 so we make sure no users are hitting issues with it.

[aprendendofelipe]

This PR does not deal with SEO concerns, but it is fully compatible with them. For example, we can add an og:image tag to the /~/** pages pointing to something like /api/thumbnail/~/**

[aprendendofelipe]

I had to remove local R2 persistence because, with PR #470, the SHA used in the tests now changes on every commit.

Regardless of #470, I believe test runs should already be isolated from each other.