Groundwork for encrypted-object replication (backlog#1783, PR-A of 3):
- classify_replication_source_encryption: accept the AES256 marker that
every stored SSE-C object carries; the SseC arm was unreachable.
- Fail closed on sealed material without an SSE marker (MinIO-written
objects) instead of replicating ciphertext as plaintext.
- Replace the dead VALID_SSE_REPLICATION_HEADERS table with a transport
map keyed by the metadata keys the SSE writer actually persists, shared
via the new rustfs_utils::http::object_encryption_keys module.
- Structurally strip all encryption metadata from outbound replication
(x-rustfs-encryption-* envelopes previously passed the filters).
- Skip decrypt_checksums for encrypted objects at the boundary so its
is_multipart=false (a response-path contract) cannot misroute
encrypted multipart objects once managed replication opens.
- Redact X-Rustfs-Replication-* SSE transport values in FileInfo Debug.
A reconciliation test pins that every key encryption_material_to_metadata
produces is either transport-mapped or stripped. All four SSE replication
e2e contracts still assert FAILED unchanged.
唐小鸭