refactor(agent-core-v2): flatten task module interface directory

- move task.ts from task/interface/ up to task/
- remove the task/interface/ barrel directory
- update imports in task barrel, taskService, and tests

packages/agent-core-v2/src/app/task/index.ts

@@ -3,6 +3,6 @@
  * Importing this barrel registers the `ITaskService` binding.
  */
 
-export * from './interface';
+export * from './task';
 import './taskService';
 export { TaskService } from './taskService';

packages/agent-core-v2/src/app/task/interface/index.ts

@@ -1 +0,0 @@
-export * from './task';

packages/agent-core-v2/src/app/task/taskService.ts

@@ -18,7 +18,7 @@ import {
   type TaskState,
   TERMINAL_TASK_STATES,
   TaskCancelledError,
-} from './interface/task';
+} from './task';
 
 function isTerminal(state: TaskState): boolean {
   return TERMINAL_TASK_STATES.has(state);

packages/agent-core-v2/test/task/task.test.ts

@@ -6,7 +6,7 @@ import {
   type IDeferredHandle,
   type TaskState,
   TaskCancelledError,
-} from '#/app/task/interface/task';
+} from '#/app/task/task';
 import { TaskService } from '#/app/task/taskService';
 
 describe('TaskService', () => {