docs: PR merge comment, coverage, mutation baseline; gitignore eval/mutants

- release-process: document PR merge comment workflow, add automation row
- gh-automation: describe CI (nextest, coverage/Codecov, PR merge comment)
- mutation-testing: state allowed-missed baseline (15)
- gitignore: mutants.out, eval/*.json, eval/artifacts, .diffscope.eval-trend

Made-with: Cursor

Author: haasonsaas

.gitignore

@@ -23,6 +23,13 @@ Thumbs.db
 *.patch
 comments.json
 review.md
+mutants.out/
+mutants.out.old/
+
+# Eval and trends
+eval/*.json
+eval/artifacts/
+.diffscope.eval-trend.json
 
 # Docker
 .dockerignore

docs/gh-automation.md

@@ -76,6 +76,11 @@ gh workflow run "Prepare release" -f version=0.5.28
 
 ## CI and runs
 
+- **Lint**: actionlint, frontend build, `cargo fmt`, `cargo clippy`.
+- **Test**: `cargo nextest run` on ubuntu/macos/windows.
+- **Coverage**: `cargo llvm-cov` → upload to Codecov. Set repo secret `CODECOV_TOKEN` to enable uploads; CI does not fail if missing.
+- **PR merge comment**: When a PR is merged, a workflow comments on each issue linked via “Closes #N”, “Fixes #N”, or “Resolves #N” in the PR body.
+
 ```bash
 # Download artifacts from latest run
 gh run download

docs/mutation-testing.md

@@ -56,4 +56,4 @@ To re-run: `cargo mutants -f '*state*'` and `cargo mutants -f '*storage_pg*'` (a
 
 ## CI
 
-The `mutation` job in `.github/workflows/ci.yml` runs mutation on the `storage_json` crate with a timeout. Update the "allowed missed" baseline in the job when you intentionally accept new equivalent mutants (and add them to the table above).
+The `mutation` job in `.github/workflows/ci.yml` runs mutation on the `storage_json` crate with a timeout. The current **allowed-missed baseline is 15**. Update the baseline in the workflow (and optionally this doc) when you intentionally accept new equivalent mutants (and add them to the table above).

docs/release-process.md

@@ -36,6 +36,7 @@ This doc and GitHub Actions make releases repeatable with minimal manual steps.
 
 - Use the **PR template** (Summary, Test plan, **Closes #N**).
 - Linking “Closes #28” in the PR body auto-closes the issue when the PR is merged.
+- When the PR is merged, the **PR merge — comment on linked issues** workflow posts a comment on each linked issue (Closes/Fixes/Resolves #N).
 
 ## Automation summary
 
@@ -46,3 +47,4 @@ This doc and GitHub Actions make releases repeatable with minimal manual steps.
 | Release body | **Release** workflow reads `RELEASE_NOTES.md` for the tagged version. |
 | Binaries + Docker | **Release** workflow builds and uploads. |
 | Issue close | Add “Closes #N” in PR body. |
+| PR merge → issue comment | **PR merge — comment on linked issues** workflow comments on each linked issue when the PR is merged. |