ipw 1.3.0

• New Maintainer: Hung Thai Tran (Research Assistant, OUCRU Biostatistics Group).
• Documentation Infrastructure: Converted all package documentation to roxygen2.
• Testing: Integrated a comprehensive suite of 22 unit tests using testthat to verify math for ipwpoint and ipwtm.
• Data Documentation: Updated haartdat variables and fixed documentation for datasets to resolve CRAN warnings.
• Examples: Corrected example line widths in .Rd files to prevent truncation in PDF manuals.
• UI: Added a README.Rmd with updated simulation examples for point-treatment and time-varying causal inference workflows.