docs(scoring): unify scan/audit/mcp-scanner/posture-assessor to v2 formula

Closes the v7.1.1 out-of-scope item: commands/scan.md:113-114 retained
the v1 formula. Exploration found two more v1 surfaces that v7.1.1
missed: commands/audit.md:46 and agents/mcp-scanner-agent.md:419, plus
agents/posture-assessor-agent.md:376 (caught by the new doc-consistency
test). Four files unified to v2 in one atomic commit.

Three-way → four-way verdict-divergence is now closed:
- scanners/lib/severity.mjs (v2, BLOCK ≥65, WARNING ≥15) — authoritative
- agents/skill-scanner-agent.md (v2 since v7.1.1)
- templates/unified-report.md (v2 since v7.1.1)
- commands/scan.md (v2 — this commit)
- commands/audit.md (v2 — this commit)
- agents/mcp-scanner-agent.md (v2 — this commit)
- agents/posture-assessor-agent.md (v2 — this commit)

New: tests/lib/doc-consistency.test.mjs walks commands/ + agents/ and
asserts NO file contains v1 formula tokens. Pinned regex set:
  - score >= 61, score >= 21, score ≥ 61, score ≥ 21
  - critical * 25, Critical × 25
  - min(100, critical*25 ...)

Plus three v2-cutoff anchors asserting commands/scan.md, commands/audit.md,
and agents/mcp-scanner-agent.md document the v2 BLOCK ≥65 cutoff (or
reference riskScore() helper).

Tests: 1523 → 1551 (+28 from doc-consistency: 25 file walks + 3 anchors).
All green.

plugins/llm-security/tests/lib/doc-consistency.test.mjs

@@ -0,0 +1,86 @@
+// doc-consistency.test.mjs — Static asserts that prose documentation
+// stays aligned with the v2 risk-scoring model in scanners/lib/severity.mjs.
+//
+// Background: v7.0.0 introduced the severity-dominated v2 risk-score model
+// (BLOCK ≥65, WARNING ≥15) but several prose surfaces (commands/, agents/)
+// continued to emit the v1 formula (`critical*25 + ...`, BLOCK ≥61,
+// WARNING ≥21). v7.1.1 fixed two of them (agents/skill-scanner-agent.md,
+// templates/unified-report.md). Batch B → v7.2.0 closes the trifecta:
+// commands/scan.md, commands/audit.md, agents/mcp-scanner-agent.md.
+//
+// This test pins the closure. If any future edit re-introduces v1 formula
+// tokens in commands/ or agents/, this test fails fast.
+
+import { describe, it } from 'node:test';
+import assert from 'node:assert/strict';
+import { readdirSync, readFileSync, statSync } from 'node:fs';
+import { join, dirname, resolve } from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __filename = fileURLToPath(import.meta.url);
+const PLUGIN_ROOT = resolve(dirname(__filename), '..', '..');
+
+// v1 formula tokens that must NOT appear in commands/ or agents/.
+// These are the patterns the brief's verification step 4 grep checks.
+const V1_TOKENS = [
+  /\bscore\s*[><]?=\s*61\b/,                        // verdict cutoff
+  /\bscore\s*[><]?=\s*21\b/,                        // verdict cutoff
+  /score\s*≥\s*61/,                                 // unicode variant
+  /score\s*≥\s*21/,                                 // unicode variant
+  /critical\s*\*\s*25/,                             // formula multiplier
+  /Critical\s*[×x]\s*25/,                           // formula multiplier (table form)
+  /min\(\s*100\s*,\s*critical\s*\*\s*25/i,          // full v1 formula prefix
+];
+
+function* walkMarkdown(dir) {
+  for (const entry of readdirSync(dir)) {
+    const full = join(dir, entry);
+    const stat = statSync(full);
+    if (stat.isDirectory()) {
+      yield* walkMarkdown(full);
+    } else if (entry.endsWith('.md')) {
+      yield full;
+    }
+  }
+}
+
+describe('doc-consistency — v1 risk-formula tokens are absent from prose', () => {
+  const COMMANDS_DIR = join(PLUGIN_ROOT, 'commands');
+  const AGENTS_DIR = join(PLUGIN_ROOT, 'agents');
+
+  for (const dir of [COMMANDS_DIR, AGENTS_DIR]) {
+    for (const file of walkMarkdown(dir)) {
+      const rel = file.replace(PLUGIN_ROOT + '/', '');
+      it(`${rel} contains no v1 formula tokens`, () => {
+        const content = readFileSync(file, 'utf-8');
+        for (const token of V1_TOKENS) {
+          assert.equal(
+            token.test(content),
+            false,
+            `${rel} still contains v1 formula token matching ${token}. ` +
+              `v7.2.0 unified all command/agent prose to v2 (BLOCK ≥65, WARNING ≥15). ` +
+              `If a new file legitimately needs to reference v1 (e.g. CHANGELOG history), ` +
+              `move that file out of commands/ or agents/.`,
+          );
+        }
+      });
+    }
+  }
+});
+
+describe('doc-consistency — v2 cutoffs are documented in unified prose', () => {
+  it('commands/scan.md mentions the v2 BLOCK cutoff (≥ 65)', () => {
+    const content = readFileSync(join(PLUGIN_ROOT, 'commands', 'scan.md'), 'utf-8');
+    assert.match(content, /score\s*[≥>=]+\s*65/);
+  });
+
+  it('commands/audit.md references riskScore() (v2 helper)', () => {
+    const content = readFileSync(join(PLUGIN_ROOT, 'commands', 'audit.md'), 'utf-8');
+    assert.match(content, /riskScore/);
+  });
+
+  it('agents/mcp-scanner-agent.md mentions the v2 BLOCK cutoff (≥ 65)', () => {
+    const content = readFileSync(join(PLUGIN_ROOT, 'agents', 'mcp-scanner-agent.md'), 'utf-8');
+    assert.match(content, /score\s*[≥>=]+\s*65/);
+  });
+});