fix: close implements tracker gap and clarify closing keywords (#110)

docs/llm-workflow-runbooks.md

@@ -227,7 +227,7 @@ tied to an issue number so the work is traceable end to end:
 | Issue | `#123` (claimed with `status:in-progress`) |
 | Branch | `(fix\|feat\|docs\|chore)/issue-123-<slug>` (review: `review/pr-456-<slug>`) |
 | Worktree | `branches/fix-issue-123-<slug>` (slashes → hyphens) |
-| PR | body says `Closes #123` (closes) or `Refs #123` (related) |
+| PR | body says `Closes #123` or `Fixes #123` (closes issue); `Implements #123` or `Refs #123` (does NOT close) |
 | Cleanup | remove remote+local branch + worktree folder; drop `status:in-progress` |
 
 `scripts/worktree-start` **rejects** implementation branches that are not