fix(delegate-task): include category in continuation task_metadata blocks

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/delegate-task/background-continuation.ts

@@ -75,6 +75,7 @@ ${buildTaskMetadataBlock({
     return formatDetailedError(error, {
       operation: "Continue background task",
       args,
+      category: task.category,
       sessionID: taskID,
     })
   }

src/tools/delegate-task/sync-continuation.ts

@@ -156,6 +156,7 @@ ${buildTaskMetadataBlock({
         agent: resumeAgent,
       })}`
    } finally {
+        category: args.category,
      if (toastManager) {
        toastManager.removeTask(taskId)
      }