fix(estimators): make RAINPROOF score orientation configurable

[ArtemVazh]

Summary

• keep uncertainty as the default orientation, where higher scores mean greater uncertainty
• add score_type="rainproof" to return the original positive RAINPROOF divergence/distance orientation
• distinguish estimator names by score orientation to avoid mixing cached results
• correct the Rényi divergence normalization against the uniform distribution

Usage

RenyiNeg(score_type="uncertainty")  # default: higher = more uncertain
RenyiNeg(score_type="rainproof")    # higher = farther from uniform

FisherRao(score_type="uncertainty")
FisherRao(score_type="rainproof")

This supersedes #459 while preserving Yedson54 as the author of the original orientation-fix commit.

Validation

• Black and flake8 pass for the changed files
• numerically checked uniform and peaked distributions for both orientations and Rényi alpha=0.5 / alpha=1