feat(workflow-scanner): E11 part 2 — re-interpolation + auth-bypass + WFL prefix + orchestrator

Closes E11. Three new pieces, plus integration:

1. Re-interpolation detector (Appsmith GHSL-2024-277 stealth pattern).
   The scanner now collects env: bindings (key -> source-expression
   text) by walking parsed events whose parentChain includes 'env',
   then for each `${{ env.<KEY> }}` inside run:, re-injects MEDIUM
   if the binding source matches the 23-field blacklist. This
   catches the pattern where developers apply env-indirection but
   then re-interpolate the env var in run:, which cancels the
   mitigation (template substitution happens before shell parsing).

2. Auth-bypass category (Synacktiv 2023 Dependabot spoofing).
   Detects `if: ${{ github.actor == 'dependabot[bot]' }}` and
   variants. MEDIUM, owasp: 'LLM06' (Excessive Agency). Distinct
   from injection — same expression syntax, different threat class.
   Recommendation steers users to `github.event.pull_request.user.login`.

3. severity.mjs OWASP map registration. WFL prefix added to all
   four maps:
   - OWASP_MAP['WFL'] = ['LLM02', 'LLM06']
   - OWASP_AGENTIC_MAP['WFL'] = ['ASI04']
   - OWASP_SKILLS_MAP['WFL'] = []
   - OWASP_MCP_MAP['WFL'] = []
   Empty arrays for skills/MCP are explicit, not omitted — keeps
   `Object.keys(OWASP_MAP)` symmetric across maps.

4. scan-orchestrator.mjs registration. workflowScan added between
   supply-chain and toxic-flow (toxic-flow correlates after primaries).
   Verified via integration: orchestrator emits 9 WFL findings on
   tests/fixtures/workflows/.

Bug fix: extractTriggers in workflow-yaml-state.mjs was collecting
sub-properties (`branches:`, `types:`) as triggers. Now tracks the
first nested indent level and ignores anything deeper.

Tests:
- 6 new cases in tests/scanners/workflow-scanner.test.mjs:
  re-interp TP, no-double-count, auth-bypass TP, auth-bypass FP
  (startsWith head_ref is not auth-bypass), OWASP map shape,
  orchestrator import + SCANNERS array entry.
- 2 new fixtures: tp-reinterpolation.yml, auth-bypass-dependabot.yml.
- Existing 14 scanner tests + 15 state-machine tests unchanged.

Test count: 1732 -> 1738 (+6). Wave B total: +53 over baseline 1685.
Pre-compact-scan flake unchanged (passes in isolation).

plugins/llm-security/tests/fixtures/workflows/.github/workflows/auth-bypass-dependabot.yml

@@ -0,0 +1,14 @@
+name: dependabot trust check (auth-bypass — Synacktiv 2023)
+on:
+  pull_request_target:
+    branches: [main]
+
+jobs:
+  auto-merge:
+    runs-on: ubuntu-latest
+    if: ${{ github.actor == 'dependabot[bot]' }}
+    steps:
+      - name: Checkout PR
+        uses: actions/checkout@v4
+      - name: Approve
+        run: gh pr review --approve

plugins/llm-security/tests/fixtures/workflows/.github/workflows/tp-reinterpolation.yml

@@ -0,0 +1,13 @@
+name: re-interpolation stealth (TP — Appsmith GHSL-2024-277)
+on:
+  pull_request_target:
+    branches: [main]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    env:
+      PR_TITLE: ${{ github.event.pull_request.title }}
+    steps:
+      - name: Looks-safe but is not
+        run: echo "${{ env.PR_TITLE }}"

plugins/llm-security/tests/scanners/workflow-scanner.test.mjs

@@ -146,3 +146,71 @@ describe('workflow-scanner — output envelope', () => {
     assert.equal(r.findings.length, 0);
   });
 });
+
+// ---------------------------------------------------------------------------
+// B4 — re-interpolation + auth-bypass categories
+// ---------------------------------------------------------------------------
+
+describe('workflow-scanner — B4 re-interpolation', () => {
+  it('flags ${{ env.PR_TITLE }} in run: when PR_TITLE was set from blacklisted source', async () => {
+    resetCounter();
+    const r = await scan(FIXTURE_DIR);
+    const fs = findingsByFile(r.findings, 'tp-reinterpolation.yml');
+    const reinterp = fs.find(f => /Re-interpolation/i.test(f.title));
+    assert.ok(reinterp, `expected a Re-interpolation finding in ${JSON.stringify(fs)}`);
+    assert.equal(reinterp.severity, 'medium');
+    assert.match(reinterp.evidence, /env\.PR_TITLE/);
+    assert.match(reinterp.description, /Appsmith|GHSL-2024-277/);
+  });
+
+  it('does not double-count: re-interpolation is emitted instead of a regular run-context finding for the env.<KEY> expression', async () => {
+    resetCounter();
+    const r = await scan(FIXTURE_DIR);
+    const fs = findingsByFile(r.findings, 'tp-reinterpolation.yml');
+    const runForEnvVar = fs.filter(f => f.evidence === '${{ env.PR_TITLE }}' && !/Re-interpolation/i.test(f.title));
+    assert.equal(runForEnvVar.length, 0);
+  });
+});
+
+describe('workflow-scanner — B4 auth-bypass', () => {
+  it('flags github.actor == "dependabot[bot]" in if: as MEDIUM auth-bypass', async () => {
+    resetCounter();
+    const r = await scan(FIXTURE_DIR);
+    const fs = findingsByFile(r.findings, 'auth-bypass-dependabot.yml');
+    const auth = fs.find(f => /Actor auth-bypass/i.test(f.title));
+    assert.ok(auth, `expected an Actor auth-bypass finding in ${JSON.stringify(fs)}`);
+    assert.equal(auth.severity, 'medium');
+    assert.equal(auth.owasp, 'LLM06');
+    assert.match(auth.recommendation, /pull_request\.user\.login/);
+  });
+
+  it('does NOT flag plain `if: ${{ startsWith(github.head_ref, …) }}` as auth-bypass', async () => {
+    resetCounter();
+    const r = await scan(FIXTURE_DIR);
+    const fs = findingsByFile(r.findings, 'fp-if-context.yml');
+    const auth = fs.filter(f => /Actor auth-bypass/i.test(f.title));
+    assert.equal(auth.length, 0);
+  });
+});
+
+describe('workflow-scanner — severity.mjs OWASP map registration', () => {
+  it('OWASP_MAP includes WFL with LLM02 and LLM06', async () => {
+    const { OWASP_MAP, OWASP_AGENTIC_MAP, OWASP_SKILLS_MAP, OWASP_MCP_MAP } =
+      await import('../../scanners/lib/severity.mjs');
+    assert.deepEqual(OWASP_MAP.WFL, ['LLM02', 'LLM06']);
+    assert.deepEqual(OWASP_AGENTIC_MAP.WFL, ['ASI04']);
+    assert.deepEqual(OWASP_SKILLS_MAP.WFL, []);
+    assert.deepEqual(OWASP_MCP_MAP.WFL, []);
+  });
+});
+
+describe('workflow-scanner — orchestrator registration', () => {
+  it('scan-orchestrator imports and lists the workflow scanner', async () => {
+    const { readFileSync } = await import('node:fs');
+    const { resolve: resolvePath } = await import('node:path');
+    const orchPath = resolvePath(import.meta.dirname, '../../scanners/scan-orchestrator.mjs');
+    const text = readFileSync(orchPath, 'utf8');
+    assert.match(text, /import\s+\{\s*scan as workflowScan\s*\}\s+from\s+['"]\.\/workflow-scanner\.mjs['"]/);
+    assert.match(text, /\{\s*name:\s*'workflow',\s*fn:\s*workflowScan\s*\}/);
+  });
+});