Per-context overlay-property overrides resolved from window-rule actions.
Each field is set only when a matching context rule fills the corresponding overlay slot (OverrideOverlayShader / OverrideOverlayStyle); an unset field falls through to the active layout's own value. Consumed daemon-side by the overlay service — see LayoutRegistry::resolveContextOverlay.
style is the OverlayDisplayMode int (0 = ZoneRectangles, 1 = LayoutPreview); the resolver maps the wire token ("rectangles" / "preview") to the int so consumers compare against the same enum the layout exposes. shaderParams holds the overridden shader's uniform values (translated by the overlay service); it is only meaningful when shaderId is set and is empty when the rule overrides only the shader id (shader defaults apply).