Reanalyze

Reanalyze re-scores and re-aggregates an existing Run archive with the current value function, estimand and normaliser, without calling the backend (ExplainRunner.reanalyze(path), mllm-shap reanalyze). It re-aggregates with the archived estimator, so it reproduces explain for the same text-based value function, and it refuses a different estimator, absence policy or partition and archives of unfinished runs.

Fixed issue: C08; decision: Manifest schema version 2.