Changes in version 1.0.0 (2026-03-29)                  

  - Initial CRAN release.
  - Implements the t-REC (iid errors) and t-RREC (robust) panel unit
    root tests from Westerlund (2015) doi:10.1016/j.jeconom.2014.09.013.
  - Supports polynomial trend degrees 0, 1, 2, ...
  - Asymptotic bias coefficients a_p and b_p computed analytically.
  - Panel-level summary statistics for heterogeneity assessment.