pre-merge-checklisted

# pre-merge-check Mechanical gate. If any step fails, do not tell the user the work is done — fix the failure first. ## Before running the mechanical gate Always run `gramaton-review` AND `gramaton-security-review` first on any substantive diff. They catch different bug classes — the mechanical gate (build/test/race/vet) confirms the code compiles and pre-existing tests pass; the reviews catch behavior-preservation regressions, vacuous tests, and security-class issues that no mechanical check reaches. Bugs surface in unexpected places — running security review on a pure-curation diff occasionally still surfaces things, and the cost is low. Skip both only for trivial diffs (typo, single-line doc change, CHANGELOG-only). ## Run in order ### 1. Build ```bash go build ./... ``` Must exit 0 with no warnings. If it fails, fix before proceeding — no point running tests against broken code. ### 2. Full test suite ```bash go test ./... ``` All green. New behavior must have new tests. If a test you didn't write fails, it's still your problem — investigate whether your change broke it. ### 3. Race detector ```bash go test -race ./... ``` Required for any change touching `core/`, `engine.go`, `index/`, `graph/`, `storage/`, any new package introduced in the diff, or anything with goroutines. Skip only for pure doc/comment/changelog PRs. ### 4. Vet ```bash go vet ./... ``` No new warnings. Existing warnings are not your problem unless you introduced them. ### 5. Changelog pr