The dequant shader returned before workgroup barriers for missing
blocks. Mask those blocks to zero so ANGLE's D3D compiler accepts the
shader while every invocation reaches each barrier.
The vcpkg ANGLE build also omitted upstream shared-context locking.
Enable both locking definitions so decode dispatches cannot race the
render thread through ANGLE's shared D3D11 state manager.
Decode each subblock from its proper bitplane offset.
Keep reconstructed wavelet levels in separate textures.
This lets inverse transforms safely write the next level.
