Route the pixel layer's base64 through the capped _b64 helper, replace
the pixels/pixels_full booleans with one pixel_mode parameter, record a
pixel skipped marker on oversized files, read EXIF from the already-read
bytes instead of re-reading the file, chunk the noise residual
convolution and replace the mgrid with 1D broadcast in the FFT features
(bit-identical values, ~300 MB less peak memory at 2048px), and fix the
raw-only docstring to account for the derived pixel layer.
Victor Kuznetsov
dfe69772cd