fix(lint): fix S603 in engine.py and D100 in conftest.py

- Add noqa: S603 for trusted internal C engine subprocess call
- Add module docstring to conftest.py
- Remove per-file ignores for engine.py and conftest.py from pyproject.toml

python_pkg/lichess_bot/engine.py

@@ -53,7 +53,7 @@ class RandomEngine:
 
     def _call_engine(self, args: list[str], *, timeout: float) -> str:
         try:
-            proc = subprocess.run(
+            proc = subprocess.run(  # noqa: S603 - trusted internal C engine binary
                 [self.engine_path, *args],
                 capture_output=True,
                 text=True,

python_pkg/lichess_bot/tests/conftest.py

@@ -1,3 +1,5 @@
+"""Pytest configuration and fixtures for lichess_bot tests."""
+
 from pathlib import Path
 import sys