Integration/cr2: Parity push to update main branch with the functions from the dev branch

[Diegolivia]

Added

• MDScontent() for multidimensional scaling maps of item-trait correspondence.
• LuAgree() for estimating Lu's agreement coefficient.
• ColquittHT() for Colquitt's content validity approach.
• Haiken() for Aiken's coefficient of homogeneity with bootstrap confidence intervals.
• HTmult() for Hinkin-Tracey indices.
• minimumCV() for Wilson-based minimum sample-size or critical-value calculations.
• Additional public and supporting functions for content validity analyses, including CVIpub() and Vaikenpub().
• GitHub Actions workflows for cross-platform package validation and source-package release archives.

Changed

• Added explicit validation for missing data across the package functions.
• Refactored confidence-interval calculations for MER, Aiken's V, CVI, CVR, and related coefficients.
• Expanded and improved content validity calculations across CVC, CIR, CVI, CVIR, CVR, and SVAL functions.
• Improved plotting support using ggplot2 and added MDS plotting functionality.
• Expanded and regenerated package documentation.
• Updated package metadata, namespace exports, dependencies, README, and repository documentation.

Fixed

• Corrected documentation, namespace, and package-structure issues identified during CRAN-style validation.
• Improved handling of package examples and test execution.
• Added package build exclusions and validation checks for clean source-package archives.