Clarify trace comments

Author: josephschorr

authzed/api/v1/debug.proto

@@ -85,9 +85,15 @@ message CheckDebugTrace {
   // compute this result, expires (if any). This is *not* related to the caching window.
   google.protobuf.Timestamp optional_expires_at = 10;
 
-  // trace_id is a unique identifier for this trace. This identifier is only guaranteed
-  // to be unique within the same overall Check or CheckBulk operation.
-  string trace_id = 11;
+  // trace_operation_id is a unique identifier for this trace's operation, that will
+  // be shared for all traces created for the same check operation in SpiceDB.
+  //
+  // In cases where SpiceDB performs automatic batching of subproblems, this ID can be used
+  // to correlate work that was shared across multiple traces.
+  //
+  // This identifier is generated by SpiceDB, is to be considered opaque to the caller
+  // and only guaranteed to be unique within the same overall Check or CheckBulk operation.
+  string trace_operation_id = 11;
 
   // source holds the source of the result. It is of the form:
   // `<sourcetype>:<sourceid>`, where sourcetype can be, among others: