Remove cleanup_temp_files() function that was deleting fixed-name files
(metadata.json, transcription.json) without verifying script ownership.
This addresses security concern raised by Codex review:
- Risk: Could delete user's existing files with same names
- Solution: Removed cleanup since no temp JSON files are actually created
Changes:
- Remove cleanup_temp_files() function entirely
- Remove --keep-temp argument (no longer needed)
- Remove all cleanup_temp_files() calls
Fixes#62 (review comment)