added more doccumentation on desired_bin_effect

[raptor419]

Update from 2.2.0 to 2.2.1

• Expanded documentation for protective and high_risk modes.
• Added details about RMST direction testing, fitness gating, adaptive thresholds, covariates, fallback behavior, and output encoding.
• Added configuration and worked examples.
• Kept the main overview concise.
• Updated package and documentation versions to 2.2.1.

No algorithmic behavior changed from 2.2.0.