Windowed gallery test projects blood / dirt / dent decals (procedural splat, noise and concave-normal art) onto a checker floor, reads the frame back and saves build/<plat>/test/out/decal/decal_gallery.png for visual review.
Adds the common-layer IDecalQuery capability (spawn/remove/clear/count/setLimit with an opaque texture handle) provided by the decal module at construction, so editor/devtools can drive decals without linking the module; adds a Squirrel script test (decal.nut + DecalScriptTest) covering eve.Decal() getName/clearAll/setLimit/update, and a C++ capability consumer test.
Completes the PBR surface-parameter layer: mesh3d.frag now blends normal / roughness / metallic / emissive (in addition to albedo) from the DecalLayer before lighting; decals are drawn as grouped instanced draws (112B per-instance SSBO, alpha-over non-premultiplied layer, per-decal uvRect/atlas + channel strengths + blend mode API); DecalManager gains frustum + distance culling and setUvRect/setTextures/setBlend; new headless readback readDecalLayerToImageData validates the pass without a swapchain. Fixes two Vulkan validation violations found by the layer (missing vertex/index binds on instanced draws, blend attachmentCount).
西风逍遥游