unhexmem_full() ignores whitespace, so a 64-byte manifest digest field
can decode to fewer than 32 bytes. Reject that while parsing instead.
[ 83.883087] TEST-72-SYSUPDATE.sh[5995]: systemd-sysupdate: ../src/src/sysupdate/sysupdate-resource.c:581: resource_load_from_web: Assertion `h.iov_len == sizeof(instance->metadata.sha256sum)' failed.
Follow-up for 43cc7a3ef4
Assisted-by: kres (claude-opus-4-7)
Co-developed-by: Claude Opus 4.8 <noreply@anthropic.com>