feat(spec): Add PauseTask and ResumeTask methods to A2A service.

specification/grpc/a2a.proto

@@ -59,6 +59,28 @@ service A2AService {
       }
     };
   }
+  // Pause a task.
+  rpc PauseTask(PauseTaskRequest) returns (Task) {
+    option (google.api.http) = {
+      post: "/{name=tasks/*}:pause"
+      body: "*"
+      additional_bindings: {
+        post: "/{tenant}/{name=tasks/*}:pause"
+        body: "*"
+      }
+    };
+  }
+  // Resume a task.
+  rpc ResumeTask(ResumeTaskRequest) returns (Task) {
+    option (google.api.http) = {
+      post: "/{name=tasks/*}:resume"
+      body: "*"
+      additional_bindings: {
+        post: "/{tenant}/{name=tasks/*}:resume"
+        body: "*"
+      }
+    };
+  }
   // Cancel a task.
   rpc CancelTask(CancelTaskRequest) returns (Task) {
     option (google.api.http) = {
@@ -202,6 +224,8 @@ enum TaskState {
   // client. Authentication is expected to come out-of-band thus this is not
   // an interrupted or terminal state.
   TASK_STATE_AUTH_REQUIRED = 8;
+  // Represents the status a task was paused and could be resumed.
+  TASK_STATE_PAUSED = 8;
 }
 // --8<-- [end:TaskState]
 
@@ -483,6 +507,8 @@ message AgentCapabilities {
   repeated AgentExtension extensions = 3;
   // Indicates if the agent provides a history of state transitions for a task.
   optional bool state_transition_history = 4;
+  // Indicates if the agent supports pause and resume of tasks.
+  optional bool pause_resume = 5;
 }
 // --8<-- [end:AgentCapabilities]
 
@@ -775,6 +801,28 @@ message ListTasksResponse {
 }
 // --8<-- [end:ListTasksResponse]
 
+// --8<-- [start:PauseTaskRequest]
+// Represents a request for the `tasks/cancel` method.
+message PauseTaskRequest {
+  // Optional tenant, provided as a path parameter.
+  string tenant = 2;
+  // The resource name of the task to cancel.
+  // Format: tasks/{task_id}
+  string name = 1;
+}
+// --8<-- [end:PauseTaskRequest]
+
+// --8<-- [start:ResumeTaskRequest]
+// Represents a request for the `tasks/cancel` method.
+message ResumeTaskRequest {
+  // Optional tenant, provided as a path parameter.
+  string tenant = 2;
+  // The resource name of the task to cancel.
+  // Format: tasks/{task_id}
+  string name = 1;
+}
+// --8<-- [end:ResumeTaskRequest]
+
 // --8<-- [start:CancelTaskRequest]
 // Represents a request for the `tasks/cancel` method.
 message CancelTaskRequest {