OrdinaryShade v0.1.0a7

OrdinaryShade 0.1.0a7

Add typed integer atomic_compare_exchange(target, comparator, replacement)
for GPU hash tables and other lock-free integer algorithms. GLSL/SPIR-V lowers
to atomicCompSwap and returns the observed old value. Comparator and replacement
must match the scalar signed/unsigned integer target. WGSL is explicitly rejected
until equivalent backend support is implemented.

Verified by compiler type/arity tests and vxl8r GPU visible-face averaging parity,
including repeated frames, invalid identities, HDR precision and no frame-stage
uploads/allocations/waits.