s3: route versioned COPY and delete-marker off the DLM

Both create a unique version/marker file plus an atomic latest-pointer flip —
the same shape as versioned PutObject — so both now reuse FinalizeVersionedWrite
instead of the distributed lock.

finalizeCopyDestination (VersioningEnabled) and createDeleteMarker take an
optional owner + condition; when the .versions owner is known they run the
demote + pointer flip (and the precondition) atomically on that owner via
routedVersionedFinalize, rolling back the version/marker file on failure and
surfacing a precondition miss as 412. CopyObjectHandler and DeleteObjectHandler
take the routed path for versioning-enabled destinations and skip the lock;
suspended versioning, version-specific deletes, metadata-only self-copy, and the
lifecycle marker path keep the existing lock-based path.

No proto or filer changes — reuses the op from the versioned-PutObject PR.

weed/s3api/s3api_object_versioned_finalize.go

@@ -2,6 +2,8 @@ package s3api
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"net/http"
 	"strconv"
 	"time"
@@ -13,6 +15,24 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/s3api/s3err"
 )
 
+// errVersionedPreconditionFailed is returned by versioned finalize helpers whose
+// contract is (…, error) when the routed FinalizeVersionedWrite reports a failed
+// precondition, so callers can surface it as 412 rather than a generic 500.
+var errVersionedPreconditionFailed = errors.New("versioned write precondition failed")
+
+// finalizeCodeToError adapts a routedVersionedFinalize result to an error: nil on
+// success, the precondition sentinel on 412, else a generic error.
+func finalizeCodeToError(code s3err.ErrorCode) error {
+	switch code {
+	case s3err.ErrNone:
+		return nil
+	case s3err.ErrPreconditionFailed:
+		return errVersionedPreconditionFailed
+	default:
+		return fmt.Errorf("versioned finalize failed: code %v", code)
+	}
+}
+
 // objectWriteOwner returns the filer that owns all of an object's writes, or ""
 // when no ring view is available. It hashes the object key with the same prefix
 // the non-versioned path uses (routedObjectOwner), so normal, suspended, and