fix: resolve test_crtsh.py import for plugins/ directory

Same importlib fix as test_username.py -- load plugins.crtsh from
file path since plugins/ is not a Python package.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/test_crtsh.py

@@ -1,8 +1,19 @@
 """Tests for the crt.sh certificate transparency plugin."""
 
+import importlib.util
+import sys
 from datetime import datetime, timezone
+from pathlib import Path
 
-from plugins.crtsh import (
+# plugins/ is not a Python package -- load the module from file path
+_spec = importlib.util.spec_from_file_location(
+    "plugins.crtsh", Path(__file__).resolve().parent.parent / "plugins" / "crtsh.py",
+)
+_mod = importlib.util.module_from_spec(_spec)
+sys.modules[_spec.name] = _mod
+_spec.loader.exec_module(_mod)
+
+from plugins.crtsh import (  # noqa: E402
     deduplicate,
     format_result,
     is_expired,