fix(#4186): anchored status vocabulary, record-session arg guard, recount pin (#4381)

* fix(#4186): anchored status vocabulary, record-session arg guard, recount pin

Three defects from #4186:

1. normalizeStateStatus ran a first-match-wins SUBSTRING chain over the
   free-prose body Status field, so prose merely mentioning a status word
   was silently rewritten to a credible wrong token (a .planning/ path in
   Italian prose -> status: planning; verifica -> verifying; completezza ->
   completed). Recognition is now an ANCHORED whole-field match against a
   declared vocabulary (STATUS_EXACT_TOKENS + STATUS_ANCHORED_PATTERNS,
   state-document.cts) — case/whitespace-tolerant, branch-order artifacts
   preserved (Planning complete -> planning; Phase complete — ready for
   verification -> verifying). The recorded lenient fallback (#3873 row 26)
   stands: unrecognized prose passes through verbatim. Read-side consumers
   (W011, statusline) ride the same function.

2. The progress recount skew (stray *-SUMMARY.md inflating
   completed_plans) is already dead on next via #1988/PR #2016
   (countMatchedSummaries pairs summaries to plans) — verified live and
   pinned with regression rows composed against the #4129/#4359 ratchet.

3. state record-session with no args executed and wrote STATE.md; it now
   errors like state update (stopped-at or resume-file required), handler-
   side so SDK callers are covered too. Four tests pinning the bare-call
   write are updated to the new contract.

* fix(#4186): update status pins to the anchored vocabulary contract

Bench round 1 follow-ups:

- Legacy bare 'Milestone complete' kept as reader-side vocabulary
  (ADR-2207 removed the writers, not recognition of legacy files).
- state.test pins updated: 'Paused at Plan 3' and round-trip
  'Executing Plan 5' were pins of the substring guessing itself —
  the round-trip now uses the real handler form 'Executing Phase 5'.
- record-session no-op/no-fields tests repurposed to the usage-error
  contract (CLI + SDK-level ExitError), byte-unchanged assertions kept.
- statusline tests repinned: vocabulary values collapse to keywords;
  narratives render the documented first-word fallback instead of a
  guessed token. Hook doc comment updated to match.
- docs-guard exempt baseline: state.test.cjs now cites docs/CLI-TOOLS.md.
- docs/CLI-TOOLS.md: record-session signature notes the required flag.

* fix(#4186): repair a dangling sentence in the schema docstring

* test(#4186): bound the completed_plans scan regex (#2128 class)

* chore(#4186): backfill changeset PR number

---------

Co-authored-by: sim <sim@local>

scripts/lint-docs-guard-registration.exempt-baseline.cjs

@@ -191,7 +191,9 @@ const DOCS_GUARD_EXEMPT_DOCS_PATHS = {
   'runtime-name-policy.test.cjs': ['docs/customize/skills'],
   'security-prompt-injection.security.test.cjs': ['docs/notes.md'],
   'shipped-reference-cites.test.cjs': [],
-  'state.test.cjs': ['docs/CONFIGURATION.md', 'docs/reference/state-md.md'],
+  // #4186: the record-session usage-contract test cites the documented
+  // signature in docs/CLI-TOOLS.md in its explanatory comment.
+  'state.test.cjs': ['docs/CLI-TOOLS.md', 'docs/CONFIGURATION.md', 'docs/reference/state-md.md'],
   'worktree-safety.test.cjs': ['docs/SUMMARY.md'],
 };