Refactor worker control protos: separate file and use task tokens

- Move Nexus command payloads to worker_nexus_service_commands.proto
- Rename to CancelActivitiesRequestPayload/ResponsePayload
- Use task_tokens instead of workflow_execution + scheduled_event_ids
- Add file-level documentation for Nexus conventions

Author: rkannan82

temporal/api/worker/v1/message.proto

@@ -11,7 +11,6 @@ option csharp_namespace = "Temporalio.Api.Worker.V1";
 
 import "google/protobuf/duration.proto";
 import "google/protobuf/timestamp.proto";
-import "temporal/api/common/v1/message.proto";
 import "temporal/api/deployment/v1/message.proto";
 import "temporal/api/enums/v1/common.proto";
 
@@ -140,29 +139,3 @@ message PluginInfo {
     // The version of the plugin, may be empty.
     string version = 2;
 }
-
-// Container for batching multiple control tasks delivered to a worker in one Nexus operation.
-message WorkerControlTasks {
-    repeated WorkerControlTask tasks = 1;
-}
-
-// A single control task for a worker.
-message WorkerControlTask {
-    // Timestamp when this task was created.
-    google.protobuf.Timestamp create_time = 1;
-
-    oneof task {
-        CancelActivityTask cancel_activity = 2;
-    }
-}
-
-// Request to cancel running activities on this worker.
-message CancelActivityTask {
-    // The workflow execution that owns the activities.
-    temporal.api.common.v1.WorkflowExecution workflow_execution = 1;
-    // The scheduled event IDs of activities to cancel.
-    // If empty, cancel all activities for this workflow running on this worker.
-    repeated int64 scheduled_event_ids = 2;
-    // Human-readable reason for cancellation.
-    string reason = 3;
-}

temporal/api/worker/v1/worker_nexus_service_commands.proto

@@ -0,0 +1,49 @@
+syntax = "proto3";
+
+package temporal.api.worker.v1;
+
+option go_package = "go.temporal.io/api/worker/v1;worker";
+option java_package = "io.temporal.api.worker.v1";
+option java_multiple_files = true;
+option java_outer_classname = "WorkerNexusServiceCommandsProto";
+option ruby_package = "Temporalio::Api::Worker::V1";
+option csharp_namespace = "Temporalio.Api.Worker.V1";
+
+// (--
+/////////////////////////////////////////////////////////////////////
+// This file contains:
+// - Conventions between server and worker.
+// - Definitions for commands and payloads for server-worker communication via Nexus
+//
+// COMMUNICATION PROTOCOL:
+// - Transport: Nexus tasks on task queue
+// - Server identifier: "sys-worker-service"
+// - Task queue: /temporal-sys/worker-commands/{namespace}/{worker_grouping_key}
+//
+// WORKER COMMANDS CONVENTIONS:
+//
+// - Worker commands are used to manage worker configurations, operations, etc.
+// - Command names should match names defined in the server API.
+// - Command names are provided in StartOperationRequest.Operation field.
+//
+// PAYLOAD CONVENTIONS:
+//
+// - In/out payloads namings follow the same convention as the regular API:
+// - CommandNameRequest (input payload)
+// - CommandNameResponse (output payload).
+// - Empty payload if response is not needed/not expected
+//
+// --)
+
+// 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;
+}
+
+// Response payload for the "cancel-activities" Nexus operation.
+message CancelActivitiesResponsePayload {
+    // Empty for now. Can be extended to include cancellation status per activity.
+}
+