v0.4.0

Changed

• BREAKING: Terminal state is now per-process via Rust ResourceArc instead of a global mutex
  • ExRatatui.run/1 closure now receives the terminal reference (1-arity)
  • ExRatatui.draw/1 is now ExRatatui.draw/2 (terminal reference as first argument)
  • ExRatatui.init_test_terminal/2 returns a terminal reference instead of :ok
  • ExRatatui.get_buffer_content/0 is now ExRatatui.get_buffer_content/1
  • ExRatatui.App behaviour users: no API changes
• Terminal is automatically restored when the terminal reference is garbage collected (crash safety)
• Test terminal instances are now independent, enabling async: true for rendering tests

Added

• Comprehensive API documentation: all key codes, mouse events, colors, modifiers, and App options
• Doctests for Layout, Style, Frame, all widgets, and test backend
• CONTRIBUTING.md with development setup