Change nexus operation to execute-commands with WorkerCommandsRequest/Response

Renames the cancel-activities operation to a more general execute-commands
operation that can support multiple command types. Updates proto structure
to use nested WorkerCommand with oneof for extensibility.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: rkannan82

temporal/api/worker/v1/worker_nexus_service_commands.proto

@@ -35,15 +35,34 @@ option csharp_namespace = "Temporalio.Api.Worker.V1";
 //
 // --)
 
-// Request payload for the "cancel-activities" Nexus operation.
-message CancelActivitiesRequestPayload {
-    // Task tokens identifying the activities to cancel.
-    // Each token corresponds to a specific activity task that the worker received.
-    repeated bytes task_tokens = 1;
+// Request payload for the "execute-commands" Nexus operation.
+message WorkerCommandsRequest {
+    repeated WorkerCommand commands = 1;
+
+    message WorkerCommand {
+        oneof type {
+            CancelActivity cancel_activity = 1;
+        }
+    }
+
+    message CancelActivity {
+        // Task token identifying the activity to cancel.
+        bytes task_token = 1;
+    }
 }
 
-// Response payload for the "cancel-activities" Nexus operation.
-message CancelActivitiesResponsePayload {
-    // Empty for now. Can be extended to include cancellation status per activity.
+// Response payload for the "execute-commands" Nexus operation.
+message WorkerCommandsResponse {
+    repeated WorkerCommandResult results = 1;
+
+    message WorkerCommandResult {
+        oneof type {
+            CancelActivityResult cancel_activity = 1;
+        }
+    }
+
+    message CancelActivityResult {
+        // Empty for now. Can be extended to include cancellation status.
+    }
 }