chore: migrate to GitHub-builtin coverage

[JohnTitor]

PR Type

PR_TYPE

PR Checklist

• Tests for the changes have been added / updated.
• Documentation comments have been added / updated.
• A changelog entry has been made for the appropriate packages.
• Format code with the latest stable rustfmt.
• (Team) Label with affected crates and semver status.

Overview

[robjtede]

interesting, i hadn't caught wind of GH adding this... seems like it'll be a premium feature though

GitHub Code Quality will become generally available on July 20, 2026, at which point usage will incur charges. To avoid being charged, disable Code Quality before that date.

https://docs.github.com/en/code-security/how-tos/maintain-quality-code/enable-code-quality

[JohnTitor]

Yeah, that's the only concern, needs to confirm.