Add resolved appearance engine and paired theme settings

Resolve light, dark and automatic appearance centrally and publish live theme snapshots to native surfaces and the appearance portal. Add paired preset families, custom theme imports, accessibility transforms and contrast-safe transitions.

Refine the Settings gallery and Auto controls, move overrides under advanced customization, and share palette-aware switches and circular slider thumbs. Document configuration and include theme licenses and integration coverage.

README.md

@@ -21,7 +21,7 @@ lock screen, and screen sharing. Change themes and settings without restarting.
 - Scrolling and tree layouts, floating windows, and a workspace overview.
 - Configurable keyboard shortcuts and touchpad gestures.
 - Multiple monitors with fractional scaling.
-- Six theme presets, wallpapers, blur, and adjustable corners.
+- Six theme families, Light/Dark/Auto modes, custom KDL themes, wallpapers, blur, and adjustable corners.
 - Clock and sticky-note widgets.
 - Screenshots with Satty editing, screen sharing, and top-bar recording.