…ed arrays so that intermediate_memmap='zarr' does not silently leave NaNs in the output

…each on-disk chunk is read once instead of being re-read across smaller chunk boundaries

…rr path already exists

…bined so they do not accumulate on disk for the duration of the coaddition

…jection and coaddition functions including that it always reprojects in blocks and defaults block_size to auto

…ntroduced with the zarr return type

…han the output along the reprojected dimensions, reprojecting each plane in sub-tiles so the coordinate transform memory stays bounded for large planes

…ns of the input WCS to the output so coaddition works when the output WCS has fewer dimensions than the input such as a celestial only output with non_reprojected_dims

…g a tile footprint into a lower-dimensional output WCS so that non-linear variation of the reprojected WCS along those axes is captured rather than only the end points