Maintenance release

• Switch to uv
• Update README.md
• Update dependencies

Add @- syntax for reading files from stdin

For extremely long listings of files use @- as the positional argument to refer to - (stdin) as a source of file paths instead of the data itself. This syntax is in keeping with other common CLI tools.

Fix issue with PB_CLEAR

Fixes bug identified in (#1). The PB_CLEAR configuration collides with the builtin dict.clear() method.

Initial release

This will probably be the only release.