feat(ci): report test coverage on PRs

[dawsontoth]

Summary

Surfaces vitest coverage in CI, outside of Sonar (closes #1319):

• Verify PR now runs pnpm test:coverage instead of pnpm test.
• A new Report coverage step (davelosert/vitest-coverage-report-action, pinned to the v2.12.1 commit SHA like the other actions) posts a sticky PR comment with the coverage table — statements/branches/functions/lines plus per-file detail for files changed in the PR — and writes the same table to the workflow job summary.
• vitest.config.ts adds the json-summary and json coverage reporters the action reads (lcov stays for Sonar), plus reportOnFailure: true so coverage still posts when tests fail (the report step runs if: always()).
• Adds an explicit permissions block (contents: read, pull-requests: write) so the action can create/update its comment.

Notes

• Verified locally: pnpm test:coverage produces coverage/coverage-summary.json and coverage/coverage-final.json, the action's default input paths; /coverage is already gitignored.
• The PR comment requires a same-repo PR (fork PRs would still get the job summary, just no comment).
• This very PR should demonstrate the comment once the workflow runs.

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request updates the Vitest configuration in vitest.config.ts to include json-summary and json coverage reporters, and enables reportOnFailure to ensure coverage reports are generated even when tests fail. There are no review comments, and I have no feedback to provide.

[github-actions]

Coverage Report

Status	Category	Percentage	Covered / Total
🔵	Lines	46.95%	4393 / 9356
🔵	Statements	47.3%	4687 / 9909
🔵	Functions	38.99%	1049 / 2690
🔵	Branches	39.27%	2852 / 7262

File Coverage

No changed files found.

Generated in workflow #1414 for commit 9c3d2e5 by the Vitest Coverage Report Action