chore(migration): per-repo gitignore/gitleaks/mailmap re-rooting

docs/marketplace-polyrepo-migration/migration/20-rehome-config.test.mjs

@@ -0,0 +1,47 @@
+// Step 4 test — re-rooted .gitignore, M7 gitleaks fingerprint, .mailmap copy, no-fingerprint plugin.
+// Pattern: plugins/config-audit/tests/lib/*.test.mjs. Runs against freshly extracted repos in $WORK.
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { spawnSync } from 'node:child_process';
+import { existsSync, readFileSync } from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+const SCRIPT = path.join(here, '20-rehome-config.sh');
+const WORK = process.env.WORK || '/tmp/polyrepo-migration';
+
+function rehome(key) {
+  const r = spawnSync('bash', [SCRIPT, key], { encoding: 'utf8', env: { ...process.env, WORK } });
+  if (r.status !== 0) throw new Error(`rehome ${key} failed (${r.status}):\n${r.stdout}\n${r.stderr}`);
+  return path.join(WORK, key);
+}
+
+const llm = rehome('llm-security');
+const gh = rehome('graceful-handoff');
+
+test('re-rooted .gitignore ignores .claude/ and carries no plugins/ prefix', () => {
+  const gi = readFileSync(path.join(llm, '.gitignore'), 'utf8');
+  assert.match(gi, /^\.claude\/$/m, '.gitignore should ignore a root-level .claude/');
+  assert.ok(!gi.includes('plugins/'), '.gitignore must not contain a plugins/ prefix');
+});
+
+test('llm-security .gitleaksignore fingerprint is re-rooted with rule-id retained (M7)', () => {
+  const gli = readFileSync(path.join(llm, '.gitleaksignore'), 'utf8');
+  assert.match(
+    gli,
+    /^examples\/malicious-skill-demo\/evil-project-health\/lib\/telemetry\.mjs:generic-api-key:18$/m,
+    'fingerprint must be the exact re-rooted path:rule-id:line'
+  );
+  assert.ok(!gli.includes('plugins/llm-security/'), 'the plugins/llm-security/ prefix must be dropped');
+  assert.ok(gli.includes(':generic-api-key:'), 'the rule-id must be retained (else the suppression breaks)');
+});
+
+test('.mailmap is copied into the extract', () => {
+  assert.ok(existsSync(path.join(llm, '.mailmap')), '.mailmap should exist in the extract');
+});
+
+test('a plugin with no fingerprint (graceful-handoff) gets .gitleaks.toml but no .gitleaksignore', () => {
+  assert.ok(existsSync(path.join(gh, '.gitleaks.toml')), 'graceful-handoff should have .gitleaks.toml');
+  assert.ok(!existsSync(path.join(gh, '.gitleaksignore')), 'graceful-handoff should have no .gitleaksignore');
+});