weightederm 0.1.0

• Initial release.
• R interface to the weightederm Python package via reticulate.
• Six estimators: werm_least_squares(), werm_huber(), werm_logistic(), and their cross-validated variants werm_least_squares_cv(), werm_huber_cv(), werm_logistic_cv().
• S3 methods: print(), summary(), predict(), coef().
• weightederm_configure_python() helper for pointing reticulate at the correct Python environment.
• All changepoint indices returned in 1-indexed R convention.