tvbounds - Sensitivity Analysis and Bounds under Total Variation Neighborhoods

Implements the sensitivity analysis framework of Palomba (2026) "Sensitivity Analysis in Population Shares" <https://filippopalomba.github.io/#jmp> for randomized experiments with attrition, counterfactuals in structural models, and recentered instrumental variables. Computes and plots sensitivity bounds together with their confidence intervals and robustness summary measures.