"never_convert_lossy_files" double negative is confusing

### Problem

Use of a double negative with a "yes" or "no" answer is confusing for the user.
"never_convert_lossy_files" - "yes" - does it mean: "yes, never convert" or "yes, actually convert"
"never_convert_lossy_files" - "no" - does it mean: "no, never convert" or "no, actually convert"

If you read the documentation, it says that "yes" means "lossy files are always copied".
If there were no double negative, this would be a self-explanatory option: "convert_lossy_files" with a "yes" or "no" answer.

Please consider renaming the option to make it easier to understand.

Start by locating the `never_convert_lossy_files` option and the documentation that explains its yes/no behavior. Trace where the option is defined and consumed, then determine the compatibility and documentation updates needed for a clearer name. Done means the option's behavior is unambiguous and the documentation matches it.

Written by the indexing model from the issue text.