Ellis improvement

Storyboard : https://www.figma.com/design/Ro8At5n14qjgn0y3KMINDi/1-1-Inquiry?node-id=0-1

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Currently, the 1:1 inquiry response feature manages only the status of a response, while response history is not preserved.

As a result:

- Responses saved during the On progress stage are not retained as history
- The final Completed response overwrites all previous responses
- Once a response is saved as Completed, all prior customer communications from the On progress stage are no longer visible on the B2C screen
- The data cannot be used for CS history tracking, handover between agents, or internal audit purposes

👉 A shift from a State-based structure to a History-based structure is required.

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현재 1:1 문의 답변 : 상태값만 관리되고, 답변 이력은 관리되지 않는 구조임.

그 결과:

- On progress 단계에서의 답변이 저장되었음에도 이력으로 남지 않음
- Completed 최종 답변이 이전 답변을 덮어씀
- B2C에서도 Completed 답변이 저장된 순간 On progress 단계의 고객 커뮤니케이션이 전혀 보이지 않음
- CS 히스토리 추적, 인수인계, 감사 목적 데이터로 활용 불가

👉 상태(State) 중심 구조 → 이력(History) 중심 구조로 전환 필요