RuboCop configuration for promptfoo Ruby files

AllCops: TargetRubyVersion: 3.0 NewCops: enable Exclude: - 'node_modules//*' - 'dist//' - 'examples/**/'

The wrapper method needs more than 10 lines to handle class methods, script loading, etc.

Metrics/MethodLength: Max: 15

Allow some complexity in the wrapper for argument handling

Metrics/AbcSize: Max: 20

The wrapper uses global variables ($LOAD_PATH) intentionally

Style/GlobalVars: Enabled: false