add mpv configuration

[CelticBoozer]

Description

Type of Change

• Bug fix
• New feature/configuration
• Refactoring (no functional changes)
• Documentation update
• Other (please describe):

Checklist

• I have read and followed the .
• The code or configuration is properly tested.
• All changes are documented in the appropriate .md file or within comments.
• No configuration files (e.g., .bashrc, .zshrc, sway/config) are
  broken or misconfigured.
• I have manually verified that all new configurations work as expected.
• I have updated the README or documentation if necessary.
• I have considered backward compatibility for existing setups.
• I have linted and formatted my code/config files if applicable.

Testing

Screenshots (if applicable)

Additional Notes