- Cache a VkFramebuffer per texture to avoid creating/destroying one for
every Blit() call.
- Create and cache both linear and nearest samplers; honor
Texture::Interpolation in descriptor writes.
- Add single-channel image-view component swizzle (R -> RGB, A = 1) to
match OpenGL grayscale behavior.
- Set texture-enable uniforms (NAME_enabled) when shaders declare them.
- Guard Blit() with null destination and emit a clear warning instead of
recording an invalid render pass.
ctest passes 4/4 in both dynamic-backend ON and OFF builds.
Mike-Solar
e908786d43