docs(agent): re-add the work-log rule, restricted to one file

Rule 1 lost its work-log sentence in the point-of-use rewrite. Restoring it plainly would
re-create the old failure, where one agent kept logs in fifty-odd files and none of them
was the place to look. So the restored rule names the file: a single page in the
knowledge base — omp-docs/log.md here, whichever change-log page a repo's index names
elsewhere — read before starting, written in the same commit as the change it describes,
under that page's own entry law. Explicitly banned: per-directory logs, per-project or
per-run logs, NOTES.md/PROGRESS.md/STATUS.md/worklog/, dated diaries. If a KB has no log
page, the fix is one at its root plus an index entry, never a log somewhere else.

The bundle's own log records the change and the two-log incident it came out of.

omp-docs/log.md

@@ -16,6 +16,27 @@ lesson, a few lines. Full incident narratives are recoverable from git
 (`git log --follow omp-docs/log.md`); knowledge that outlives an entry lives
 on its concept page, linked here. Never re-expand an entry in place.
 
+This page is the bundle's **only** work log: one file, at the root. Never start a
+second one in a subdirectory or under another name — `scripts/kb-lint.sh` reports any
+`log.md` that is not this one.
+
+## 2026-10-20 — one work log per bundle
+
+The bundle had two: this page and `core/log.md`, created "for tracking core
+directory modifications" — two entries of pure migration bookkeeping (file moved,
+directory created, log created), and a date for the OKF conversion that neither this
+page nor git agrees with: 2026-07-15 there, 2026-01-15 here, while `git log` dates the
+OKF rebuild 2026-08-28. `core/index.md` was still pointing readers at it, which is how
+a stale page stays alive. Trashed to `omp-docs/core/.AGENTTRASH/log.md` — its content
+is recoverable from git, which is the entire argument against a second log.
+
+Laws, now written down in [references/okf-spec.md](references/okf-spec.md) and
+[references/okf-maintenance.md](references/okf-maintenance.md), and gated: a bundle has
+ONE work log, `log.md`, at its root, and `scripts/kb-lint.sh` reports any `log.md` that
+is not the root's — so the sprawl that made logging useless once cannot restart
+quietly. The agent-side duty is in `agent/APPEND_SYSTEM.md` § 1: log here, read here,
+never start another.
+
 ## 2026-10-20 — two instruments rescued from `$HOME` script sediment
 
 `$HOME` had accumulated 123 loose scripts at its root (archived to