causalplot 0.2.1

• Prepare for CRAN submission.
• Add run_app() function to launch an interactive Shiny app for building diagrams.
• Switch to MIT license.
• Increase maximum allowed lines per box from 3 to 5.
• Fix R CMD check notes (non-portable filenames, explicit exports).

causalplot 0.2.0

• Add new templates: 211, 221, and 2221 for multi-IV designs.
• Add typology() function for creating 2x2 typology diagrams.
• Reduce whitespace around plots with auto-computed axis limits.
• Add 111_moderator and 111_confounder templates.

causalplot 0.1.0

• Initial release on GitHub.
• Core causal_plot() function with templates: 111, 1111, 11111, 1121, 1211, 1221, and bathtub.
• Customizable labels, colors, fonts, corner radius, and arrow styles.
• Built on ggplot2, ggforce, and ggtext.