Gaussian blur (three box passes each way, running sums per 16-pixel chunk), the
separable resample with the CPU's exact taps (uploaded tables), the guided filter
and the fast guided filter (coefficients on the subsampled grid), log luminance,
dark channel + airlight (percentile of every 7th value read back), white balance
and luminance/colour noise reduction now run as WGSL kernels. A render records
everything into one command encoder and reads back only the output (and the
airlight samples); defringe and spot removal still run on the CPU when used.
Equivalence unchanged: max 1 LSB, mean < 0.001 LSB over all test cases.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>