D056 - The header past 0x410 was entirely zero, so nothing could be mounted

The header past 0x410 was entirely zero, and a package whose header says its image is zero bytes long has nothing to mount.

This crate wrote four header fields: the magic, the entry count, the table offset and the image offset. A real package's header carries far more, and the block at 0x400 is the part a console uses to find and size the image - pfs_image_size, package_size, pfs_flags, pfs_signed_size, pfs_cache_size, and two digests over the image.

All of it was measured out of a real package with xxd -s 0x400 and matches LibOrbisPkg's writer offset for offset. Two constants settle it beyond coincidence: a version date of 0x20161020 and a version hash of 0x1738551, both appearing verbatim in the sample and in the source. A generated header's first sixteen bytes and its whole 0x400 block are now byte-identical in shape to a real one, and package_size is the file's exact length.

The image also moved to 0x80000. Packing it in behind the entries was legal by the format - the header names the offset - but every real package and LibOrbisPkg both put it there, and "legal by the format" is a weaker claim than "identical to every sample" when the reader is a machine nobody here can attach a debugger to.

That move broke the block-digest table, which had been sizing itself from the old computed offset. The test that re-runs the derivation against this crate's own output caught it immediately, which is the entire reason that test exists.