New features
- Added convert --output-file FILE with alias -o.
- Supports exact final output path for single-book conversions.
- Rejects --output-file with positional destination, directory input, or archive sources resolving to multiple FB2 books.
- Preserves --overwrite behavior for exact output files.
- Ignores output_name_template and --nodirs in exact output mode.
Full Changelog: v1.5.2...v1.5.3