feat(10-03): add setAgentQuestion convenience helper

- Add single-question convenience method to TestHarness
- Wraps question in array for questions scenario
- Keeps setAgentQuestions for multi-question cases

src/test/harness.ts

@@ -197,13 +197,24 @@ export interface TestHarness {
   setAgentDone(agentName: string, result?: string): void;
 
   /**
-   * Convenience: Set agent to ask questions.
+   * Convenience: Set agent to ask questions (array form).
    */
   setAgentQuestions(
     agentName: string,
     questions: QuestionItem[]
   ): void;
 
+  /**
+   * Convenience: Set agent to ask a single question.
+   * Wraps the question in an array internally.
+   */
+  setAgentQuestion(
+    agentName: string,
+    questionId: string,
+    question: string,
+    options?: Array<{ label: string; description?: string }>
+  ): void;
+
   /**
    * Convenience: Set agent to fail with unrecoverable error.
    */
@@ -311,6 +322,18 @@ export function createTestHarness(): TestHarness {
       agentManager.setScenario(agentName, { status: 'questions', questions });
     },
 
+    setAgentQuestion: (
+      agentName: string,
+      questionId: string,
+      question: string,
+      options?: Array<{ label: string; description?: string }>
+    ) => {
+      agentManager.setScenario(agentName, {
+        status: 'questions',
+        questions: [{ id: questionId, question, options }],
+      });
+    },
+
     setAgentError: (agentName: string, error: string) => {
       agentManager.setScenario(agentName, { status: 'unrecoverable_error', error });
     },