Debug: Remove temporary debug logging for author metadata

Removed debug print statements that were added to investigate author
extraction issues. The fix is confirmed working - authors are being
correctly extracted from the Audiobookshelf 'authors' array field.

Confirmed via logs and database:
- Audiobookshelf uses 'authors' array, not 'authorName' string
- extract_author_name() function correctly handles this structure
- All books now have proper author names (e.g., "Orson Scott Card")

Debug logging is no longer needed.

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