docs(P12): complete gitignore-credential-hygiene phase (v1.13.15)

---ci---
project: acdl
phase: 12
milestone: v1.14
status: complete
requirements:
  covered: [REQ-146]
  partial: []
---/ci---

.gitignore

@@ -18,4 +18,14 @@ terraform/bootstrap/.bootstrap_state.json
 **/.terraform/
 **/.terraform.lock.hcl
 **/tfplan
-**/*.tfstate*
+**/*.tfstate*
+
+# Credential patterns (v1.14, REQ-146)
+*.pem
+*.key
+*.p12
+*.pfx
+*.cer
+*.crt
+*.jks
+*.keystore

tests/test_no_secrets_tracked.py

@@ -0,0 +1,35 @@
+"""v1.14 (REQ-146): no credential-looking files are tracked by git."""
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+ROOT = Path(__file__).resolve().parent.parent
+
+CREDENTIAL_EXTENSIONS = [".pem", ".key", ".p12", ".pfx", ".cer", ".crt", ".jks", ".keystore"]
+
+
+def test_no_credential_files_tracked():
+    """Assert no file with a credential extension is tracked by git."""
+    result = subprocess.run(
+        ["git", "ls-files"],
+        cwd=str(ROOT),
+        capture_output=True,
+        text=True,
+    )
+    if result.returncode != 0:
+        pytest.skip("git not available or not a repo")
+    tracked = result.stdout.strip().split("\n")
+    cred_files = [
+        f for f in tracked
+        if any(f.endswith(ext) for ext in CREDENTIAL_EXTENSIONS)
+    ]
+    assert cred_files == [], f"credential files tracked by git: {cred_files}"
+
+
+def test_gitignore_has_credential_patterns():
+    """Assert .gitignore contains the credential-pattern catch-all."""
+    gitignore = (ROOT / ".gitignore").read_text()
+    for ext in [".pem", ".key", ".p12", ".pfx"]:
+        assert f"*{ext}" in gitignore, f".gitignore missing credential pattern *{ext}"