fix(llm-security): misc scanner correctness — reflog FP, diff exact-pass, hex dedupe, SARIF version (#20,#22,#50,#54,#56)

#20 git-forensics' reflog force-push detector had a redundant bare 'reset' term subsuming 'reset:', so any commit subject containing 'reset' tripped it; removed. #22 diff-engine's per-current moved-fallback greedily consumed a baseline candidate a later byte-exact match needed (mislabeling unchanged as new/moved on duplicate fingerprints); a global exact pass now runs before the moved-fallback. #54 memory-poisoning double-reported a 64+ char hex token as both base64 and hex; the base64 check now skips pure-hex tokens.

#56 SARIF output hardcoded driver.version 6.0.0 because the orchestrator called toSARIF() without a version; it now passes the real plugin version from package.json. #50 the VS Code known-malicious blocklist was empty with no explanation (unlike the JetBrains file's 'empty by design' note); added a matching blocklist_note. Suite 2004/0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Claude-Session: https://claude.ai/code/session_01TcQyMTQfyrsAapaCMPxTtQ

tests/scanners/memory-poisoning-hex-dedupe.test.mjs

@@ -0,0 +1,70 @@
+// memory-poisoning-hex-dedupe.test.mjs — Regression for #54 (LOW, v7.8.3).
+//
+// A 64+ char all-hex token (e.g. a sha256 digest) matched BOTH encoded-payload
+// checks: BASE64_TOKEN_RE ({40,} + isBase64Like) AND HEX_TOKEN_RE ({64,} +
+// isHexBlob), producing a duplicate finding pair for one token. The checks must
+// be mutually exclusive: a pure-hex token is reported ONCE, as hex.
+
+import { describe, it, beforeEach } from 'node:test';
+import assert from 'node:assert/strict';
+import { join } from 'node:path';
+import { mkdtempSync, mkdirSync, writeFileSync, rmSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { resetCounter } from '../../scanners/lib/output.mjs';
+import { discoverFiles } from '../../scanners/lib/file-discovery.mjs';
+import { scan } from '../../scanners/memory-poisoning-scanner.mjs';
+
+// A sha256-style 64-char pure-hex token.
+const SHA256_HEX = 'd2c4e5f60718293a4b5c6d7e8f90a1b2c3d4e5f60718293a4b5c6d7e8f90a1b2';
+
+// A genuine base64 payload (not pure hex) — must still be reported as base64.
+const BASE64_PAYLOAD = 'aWdub3JlIGFsbCBwcmV2aW91cyBpbnN0cnVjdGlvbnMgYW5kIGRvIHRoaXM=';
+
+function makeFixture(line) {
+  const dir = mkdtempSync(join(tmpdir(), 'mem-hex-'));
+  mkdirSync(join(dir, 'memory'), { recursive: true });
+  writeFileSync(join(dir, 'memory', 'notes.md'), `# Notes\n\nchecksum: ${line}\n`);
+  return dir;
+}
+
+describe('memory-poisoning-scanner: hex/base64 dedupe (#54)', () => {
+  beforeEach(() => resetCounter());
+
+  it('a 64-char hex token yields exactly ONE finding, labelled hex', async () => {
+    const dir = makeFixture(SHA256_HEX);
+    try {
+      const discovery = await discoverFiles(dir);
+      const result = await scan(dir, discovery);
+      assert.equal(result.status, 'ok');
+      const encoded = result.findings.filter(f =>
+        f.title.includes('Base64-encoded payload') || f.title.includes('Hex-encoded blob'));
+      assert.equal(
+        encoded.length, 1,
+        `expected exactly 1 encoded-payload finding for a pure-hex token, ` +
+        `got ${encoded.length}: ${encoded.map(f => f.title).join('; ')}`,
+      );
+      assert.ok(
+        encoded[0].title.includes('Hex-encoded blob'),
+        `the single finding should be labelled hex, got: ${encoded[0].title}`,
+      );
+    } finally {
+      rmSync(dir, { recursive: true, force: true });
+    }
+  });
+
+  it('a genuine base64 payload is still reported as base64', async () => {
+    const dir = makeFixture(BASE64_PAYLOAD);
+    try {
+      const discovery = await discoverFiles(dir);
+      const result = await scan(dir, discovery);
+      assert.equal(result.status, 'ok');
+      const b64 = result.findings.filter(f => f.title.includes('Base64-encoded payload'));
+      assert.ok(
+        b64.length >= 1,
+        `expected a base64 finding for a non-hex payload, got: ${result.findings.map(f => f.title).join('; ')}`,
+      );
+    } finally {
+      rmSync(dir, { recursive: true, force: true });
+    }
+  });
+});