refactor: unify logging to standard logging.getLogger(__name__) pattern

Replace custom get_logger() wrapper with standard Python logging pattern
across executor.py and quarantine.py. Remove dead logger imports from
reports.py. Remove get_logger() function from logging_config.py and its
tests. Reduces logging patterns from 2 to 1.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/vlm/reports.py

@@ -9,15 +9,12 @@ This module provides functionality to generate various reports about the video l
 
 import csv
 import json
-import logging
 from datetime import datetime, timezone
 from io import StringIO
 from pathlib import Path
 
 from vlm.models import DuplicateGroup, MovieIdentity, SeasonCompleteness, SeriesIdentity, VideoFile
 
-logger = logging.getLogger(__name__)
-
 
 def _normalize_to_utc(timestamp: datetime) -> datetime:
     """Normalize a datetime to a UTC instant."""