feat(review): the critic's own security key SECURITY_RISK (decision 167)

lib/review/rule-catalogue.mjs gains SECURITY_RISK (BLOCKER, category
security, memory route rule): Voyage's own security key for a finding by
its own reviewers that SECURITY_INJECTION does not cover.
SECURITY_REVIEW_VULNERABILITY is described as the engines' key only.
plan-critic and scope-guardian name SECURITY_INJECTION or SECURITY_RISK
and no longer the engines' key.

The count moves from 17 to 18 in every pin: rule-catalogue.test,
claude-md-scope [CAT] (which now also refuses a stale 17), doc-consistency,
review-prose-pins, docs/architecture.md and the two reviewer agents.
critic-severity-rules pins three security keys; its "every security key
named" check leaves out the engines' key, and a new pin says the critic
never names it.

Existing tests changed for the planned rule: the four count pins above
(17 -> 18), and critic-severity-rules' two-key test (now three keys).
tests/lib/engine-findings.test.mjs: a comment naming the "(17 keys)" pin
now says 18.

Part 2, step 2.3 of the E plan.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

agents/brief-conformance-reviewer.md

@@ -33,7 +33,7 @@ You will receive a prompt containing:
   /trekreview triage gate. Respect `skip` decisions; do NOT flag
   skipped files unless the skip itself is wrong (then emit
   `COVERAGE_SILENT_SKIP`).
-- **Rule catalogue** — the 17-key catalogue in
+- **Rule catalogue** — the 18-key catalogue in
   `lib/review/rule-catalogue.mjs`. You may only emit findings whose
   `rule_key` is in this set.
 - **Success-criteria check results** — a table produced by /trekreview

agents/code-correctness-reviewer.md

@@ -37,7 +37,7 @@ You will receive a prompt containing:
   context only. The brief is not your contract — it is the conformance
   reviewer's contract. You evaluate code correctness regardless of
   what the brief promised.
-- **Rule catalogue** — the 17-key catalogue in
+- **Rule catalogue** — the 18-key catalogue in
   `lib/review/rule-catalogue.mjs`. You may only emit findings whose
   `rule_key` is in this set.
 - **Instruction files** — the repo's tracked instruction files for this

agents/plan-critic.md

@@ -290,8 +290,8 @@ implementation catches nothing, so the finding stays major. Give
 `lowered_from` and `caught_by` when you lower a finding this way.
 
 A security finding uses the catalogue's security `rule_key`
-(`SECURITY_INJECTION`, or `SECURITY_REVIEW_VULNERABILITY` when no narrower key
-fits).
+(`SECURITY_INJECTION`, or `SECURITY_RISK` when no narrower key fits); the
+engines' key is never yours.
 
 Your rating decides what happens next: `/trekplan` records your findings with
 `plan-gate.mjs --record`, and the plan gate stops the plan while any BLOCKER

agents/scope-guardian.md

@@ -108,8 +108,8 @@ implementation catches nothing, so the finding stays major. Give
 `lowered_from` and `caught_by` when you lower a finding this way.
 
 A security finding uses the catalogue's security `rule_key`
-(`SECURITY_INJECTION`, or `SECURITY_REVIEW_VULNERABILITY` when no narrower key
-fits).
+(`SECURITY_INJECTION`, or `SECURITY_RISK` when no narrower key fits); the
+engines' key is never yours.
 
 Your findings go through `plan-gate.mjs --record` with plan-critic's; an open
 blocker or major stops the plan. `severity` is exactly `blocker`, `major` or `minor`;