Map a per-channel encoding NAME to the worker decode kind. Exported so the
mapping is unit-testable — a mis-route here (e.g. geolog -> 'log') decodes
every HDR color with the wrong inverse compand and no error. Order matters:
'geolog_perchannel*' must not be caught by a 'log_perchannel' prefix test
('geolog...' does NOT start with 'log', but keep the explicit order anyway).
Map a per-channel encoding NAME to the worker decode kind. Exported so the mapping is unit-testable — a mis-route here (e.g. geolog -> 'log') decodes every HDR color with the wrong inverse compand and no error. Order matters: 'geolog_perchannel*' must not be caught by a 'log_perchannel' prefix test ('geolog...' does NOT start with 'log', but keep the explicit order anyway).