Support SimpleCov "merged" Coverage format

[noahd1]

Support for a "merged" simplecov JSON report, which is a format that we have historically supported.

This changeset is larger than initially envisioned in part because the original code used a Map data structure to capture coverage results, where the keys were file paths. Because the point of this PR is to support more than 1 coverage report for the same path, I needed to change the structure of the code to use a Vec instead of a Map.

I could have stopped there, but given the fairly good tests, I refactored until the 3 supported SimpleCov formats were a bit more clearly represented in the code.

[qltysh]

Diff Coverage: The code coverage on the diff in this pull request is 94.5%.

Total Coverage: This PR will increase coverage by 0.02%.

File Coverage Changes

Path	File Coverage Δ	Indirect
qlty-coverage/src/parser/simplecov.rs	-0.2
qlty-cloud/src/auth/auth_flow.rs	-0.5	√
qlty-cli/src/ui/unformatted.rs	0.4	√

🛟 Help

• Diff Coverage: Coverage for added or modified lines of code (excludes deleted files). Learn more.

• Total Coverage: Coverage for the whole repository, calculated as the sum of all File Coverage. Learn more.

• File Coverage: Covered Lines divided by Covered Lines plus Missed Lines. (Excludes non-executable lines including blank lines and comments.)

  • Indirect Changes: Changes to File Coverage for files that were not modified in this PR. Learn more.

[qltysh]

All good ✅