containr 0.1.3

Internal helpers renamed with a dot prefix: get_r_ver_tags() → .get_r_ver_tags(), r_ver_exists() → .r_ver_exists(), and validate_file_arg() → .validate_file_arg(). These are not user-facing but the change enforces the package convention for internal functions.
tidystudio added as a valid r_mode in generate_dockerfile(), .get_r_ver_tags(), and .r_ver_exists(). Maps to rocker/verse.

generate_dockerfile(): replaced stop() and print() / Sys.sleep() calls with cli::cli_abort() and cli::cli_inform() throughout for consistent, styled error and progress messages.
generate_dockerfile(): fixed comments condition for Quarto block from quarto_install_line == TRUE to install_quarto.
generate_dockerfile(): fixed comments conditions for code_file and misc_file blocks to check the correct variables.
generate_dockerfile(): RStudio run instructions split into two cleaner comment lines.
.get_r_ver_tags(): replaced stopifnot() with cli::cli_abort() and message() with cli::cli_inform(). Removed bare return() from final list expression.
.r_ver_exists(): replaced stop() with cli::cli_abort() and message() with cli::cli_inform().
.validate_file_arg(): replaced stop() with cli::cli_abort().

containr 0.1.2

Added inst/CITATION with DOI for proper academic citation via citation("containr")
Added inst/WORDLIST for spell check consistency
Added Language: en-US to DESCRIPTION
Improved documentation and README
Added rhub v2 GitHub Actions workflow for cross-platform checks