Extract RenderingSettings overrides from zarr viewer_config.
Returns only the fields that are set (partial object), plus — when the
scene asks for cinematic mode — the cinematic preset expanded into the
fields the scene left unset (see expandCinematicPreset below).
A recognized camera FOV preset supplies its numeric FOV when absent; a
conflicting numeric FOV wins and warns once per preset/value pair.
Extract RenderingSettings overrides from zarr viewer_config. Returns only the fields that are set (partial object), plus — when the scene asks for cinematic mode — the cinematic preset expanded into the fields the scene left unset (see
expandCinematicPresetbelow). A recognized camera FOV preset supplies its numeric FOV when absent; a conflicting numeric FOV wins and warns once per preset/value pair.