* filer use context without cancellation
* pass along context
* fix: copy to bucket with default SSE-S3 encryption fails (#7562)
When copying an object from an encrypted bucket to a temporary unencrypted
bucket, then to another bucket with default SSE-S3 encryption, the operation
fails with 'invalid SSE-S3 source key type' error.
Root cause:
When objects are copied from an SSE-S3 encrypted bucket to an unencrypted
bucket, the 'X-Amz-Server-Side-Encryption: AES256' header is preserved but
the actual encryption key (SeaweedFSSSES3Key) is stripped. This creates an
'orphaned' SSE-S3 header that causes IsSSES3EncryptedInternal() to return
true, triggering decryption logic with a nil key.
Fix:
1. Modified IsSSES3EncryptedInternal() to require BOTH the AES256 header
AND the SeaweedFSSSES3Key to be present before returning true
2. Added isOrphanedSSES3Header() to detect orphaned SSE-S3 headers
3. Updated copy handler to strip orphaned headers during copy operations
Fixes#7562
* fmt
* refactor: simplify isOrphanedSSES3Header function logic
Remove redundant existence check since the caller iterates through
metadata map, making the check unnecessary. Improves readability
while maintaining the same functionality.
