forked from 1b-agent/opencadstudio-upstream
Model space appearance now follows the active UI theme instead of a hardcoded dark background. Canvas mode is user-selectable (Match Theme / Classic CAD Dark / Custom RGB), with matching controls for the paper sheet and desk surround backgrounds and grid opacity. Implements industry-standard CAD system variables, all settable via command name, SETVAR, and the Options dialog: - COLORTHEME (0/1 dark/light UI scheme, preserves custom palettes) - COLORSCHEME (interactive named-theme selection) - BACKGROUND (THEME/CLASSIC/DEFAULT/DESK presets, RGB triplets) - SELECTIONAREA, SELECTIONAREAOPACITY (translucent marquee fill) - WINDOWSAREACOLOR/WINDOWAREACOLOR, CROSSINGAREACOLOR (ACI or theme) - SELECTIONEFFECT, SELECTIONEFFECTCOLOR (GPU highlight pass, driven by selection_generation invalidation — no retessellation) - SELECTIONPREVIEW (bit 0 = idle rollover, bit 1 = in-command hover) - GRIPSIZE, GRIPCOLOR, GRIPHOT, GRIPHOVER (grip overlay styling)