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/logging_config.py

@@ -106,21 +106,6 @@ def setup_logging(
     return logger
 
 
-def get_logger() -> logging.Logger:
-    """Get the configured VLM logger instance.
-    
-    Returns:
-        Logger instance (creates default configuration if not already set up)
-    """
-    logger = logging.getLogger("vlm")
-    
-    # If logger has no handlers, set up default configuration
-    if not logger.handlers:
-        setup_logging()
-    
-    return logger
-
-
 def log_operation(
     logger: logging.Logger,
     level: int,