feat(10-01): extend agent schema to multi-question array

- Change status from 'question' to 'questions' (plural)
- Add QuestionItem with id field for answer matching
- Update PendingQuestion to PendingQuestions with questions array
- Update AgentWaitingEvent payload to questions array
- Update ClaudeAgentManager and MockAgentManager adapters
- Update TestHarness and all test files

src/dispatch/manager.test.ts

@@ -73,7 +73,7 @@ function createMockAgentManager(
     stop: vi.fn().mockResolvedValue(undefined),
     resume: vi.fn().mockResolvedValue(undefined),
     getResult: vi.fn().mockResolvedValue(null),
-    getPendingQuestion: vi.fn().mockResolvedValue(null),
+    getPendingQuestions: vi.fn().mockResolvedValue(null),
   };
 }