Fix missing owner ID in MCP datum responses

The NewDatum type conversion helper was not mapping the OwnerID field
from the coredata struct, causing MCP responses for data resources to
return a zero-value owner_id.

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

pkg/server/api/mcp/v1/types/datum.go

@@ -23,6 +23,7 @@ func NewDatum(d *coredata.Datum) *Datum {
 	return &Datum{
 		ID:                 d.ID,
 		Name:               d.Name,
+		OwnerID:            d.OwnerID,
 		OrganizationID:     d.OrganizationID,
 		SnapshotID:         d.SnapshotID,
 		DataClassification: d.DataClassification,