fix(logging): Add structured logging module

- Created logging.py with:
  - setup_logging() function
  - Configurable levels
  - Console and file handlers
  - Structured format

This addresses the logging gap.

opus_orchestrator/logging.py

@@ -0,0 +1,61 @@
+"""Logging configuration for Opus.
+
+Structured logging with levels, formats, and handlers.
+"""
+
+import logging
+import sys
+from pathlib import Path
+
+
+def setup_logging(
+    level: str = "INFO",
+    log_file: str = None,
+    format: str = "%(asctime)s | %(levelname)-8s | %(name)s | %(message)s",
+) -> logging.Logger:
+    """Setup structured logging for Opus.
+    
+    Args:
+        level: DEBUG, INFO, WARNING, ERROR
+        log_file: Optional file path
+        format: Log message format
+        
+    Returns:
+        Configured logger
+    """
+    # Create logger
+    logger = logging.getLogger("opus")
+    logger.setLevel(getattr(logging, level.upper()))
+    
+    # Clear existing handlers
+    logger.handlers.clear()
+    
+    # Console handler
+    console = logging.StreamHandler(sys.stdout)
+    console.setLevel(getattr(logging, level.upper()))
+    console.setFormatter(logging.Formatter(format))
+    logger.addHandler(console)
+    
+    # File handler (optional)
+    if log_file:
+        log_path = Path(log_file)
+        log_path.parent.mkdir(parents=True, exist_ok=True)
+        
+        file_handler = logging.FileHandler(log_file)
+        file_handler.setLevel(logging.DEBUG)
+        file_handler.setFormatter(logging.Formatter(
+            "%(asctime)s | %(levelname)-8s | %(name)s:%(lineno)d | %(message)s"
+        ))
+        logger.addHandler(file_handler)
+    
+    return logger
+
+
+# Default logger
+logger = setup_logging()
+
+
+# Usage in modules:
+# from opus_orchestrator.logging import logger
+# logger.info("Starting generation")
+# logger.error(f"Failed: {e}")