changeRectangleAttributes
abstract fun changeRectangleAttributes(top: Int, left: Int, bottom: Int, right: Int, setMask: Int, clearMask: Int)
Applies VT420 DECCARA visual-attribute changes without changing characters or the pen.
Coordinates retain DEC's one-based inclusive representation. setMask and clearMask use io.github.ketraterm.protocol.DecRectangleAttribute bits; the parser has already collapsed ordered SGR-like parameters into their final operations.