Add attributes needed by server to propagate control tasks to worker (#711)

<!-- Describe what has changed in this PR -->
**What changed?**

Added worker_control_task_queue to poll requests:
- PollActivityTaskQueueRequest
- PollWorkflowTaskQueueRequest
Note: worker_instance_key was already added to these requests in #686.

Added worker_instance_key and worker_control_task_queue to: 
- RespondWorkflowTaskCompletedRequest: This API is used to eagerly fetch
activity.

<!-- Tell your future self why have you made these changes -->
**Why?**
To enable server to send control tasks to worker. Each worker provides a
worker_control_task_queue (a dedicated per-worker Nexus task queue) so
the server can send control tasks directly to it.

Example flow:
- User cancels a workflow.
- Server sends activity cancellation tasks to all workers that could be
processing activities belonging to that workflow.
- Worker will receive the cancellation message even when activity
heartbeat is not enabled.

<!-- Are there any breaking changes on binary or code level? -->
Breaking changes: None
[Server PR](temporalio/temporal#9231)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

temporal/api/workflowservice/v1/request_response.proto

@@ -265,6 +265,11 @@ message PollWorkflowTaskQueueRequest {
     // A unique key for this worker instance, used for tracking worker lifecycle.
     // This is guaranteed to be unique, whereas identity is not guaranteed to be unique.
     string worker_instance_key = 8;
+
+    // A dedicated per-worker Nexus task queue on which the server sends control
+    // tasks (e.g. activity cancellation) to this specific worker instance.
+    string worker_control_task_queue = 9;
+
     // Deprecated. Use deployment_options instead.
     // Each worker process should provide an ID unique to the specific set of code it is running
     // "checksum" in this field name isn't very accurate, it should be though of as an id.
@@ -385,6 +390,14 @@ message RespondWorkflowTaskCompletedRequest {
     // Worker deployment options that user has set in the worker.
     temporal.api.deployment.v1.WorkerDeploymentOptions deployment_options = 17;
 
+    // A unique key for this worker instance, used for tracking worker lifecycle.
+    // This is guaranteed to be unique, whereas identity is not guaranteed to be unique.
+    string worker_instance_key = 19;
+
+    // A dedicated per-worker Nexus task queue on which the server sends control
+    // tasks (e.g. activity cancellation) to this specific worker instance.
+    string worker_control_task_queue = 20;
+
     // SDK capability details.
     message Capabilities {
         // True if the SDK can handle speculative workflow task with command events. If true, the
@@ -450,6 +463,11 @@ message PollActivityTaskQueueRequest {
     // A unique key for this worker instance, used for tracking worker lifecycle.
     // This is guaranteed to be unique, whereas identity is not guaranteed to be unique.
     string worker_instance_key = 8;
+
+    // A dedicated per-worker Nexus task queue on which the server sends control
+    // tasks (e.g. activity cancellation) to this specific worker instance.
+    string worker_control_task_queue = 9;
+
     temporal.api.taskqueue.v1.TaskQueueMetadata task_queue_metadata = 4;
     // Information about this worker's build identifier and if it is choosing to use the versioning
     // feature. See the `WorkerVersionCapabilities` docstring for more.