메시지 좋아요 싫어요 토글 동작 수정

채팅 메시지 피드백 버튼 로직을 shared feedback 상태 기반으로 다시 구성해 좋아요와 싫어요가 모두 즉시 반응하고 상호배타적으로 동작하도록 정리했다.

좋아요는 활성 색상과 chip 배경으로 상태가 확실히 보이게 바꾸고, 싫어요를 다시 누르면 null 상태로 정상 해제되도록 수정했다.

README와 DEVELOPMENT 문서를 2026-04-06 18:09 (KST) 기준으로 갱신했고 dotnet build 검증에서 경고 0 / 오류 0을 확인했다.

docs/DEVELOPMENT.md

@@ -4997,3 +4997,5 @@ ow + toggle ?쒓컖 ?몄뼱濡??ㅼ떆 ?뺣젹?덈떎.
 - Document update: 2026-04-06 18:02 (KST) - Added IBM deployment-chat detection in `LlmService.cs` for vLLM registered models using `ibm_iam` or `cp4d_*` auth with `/ml/v1/deployments/...`-style endpoints. These requests now use IBM deployment chat URLs (`/text/chat` or `/text/chat_stream`) instead of appending `/v1/chat/completions`.
 - Document update: 2026-04-06 18:02 (KST) - Added an IBM deployment request body builder in `LlmService.cs` that omits OpenAI-style `model` and `stream` fields and sends `messages + parameters` instead. This directly addresses IBM responses complaining that `model_id` or `mode` must not be specified in the request body.
 - Document update: 2026-04-06 18:02 (KST) - Hardened vLLM response handling for IBM deployment endpoints by accepting `results[].generated_text`, `output_text`, and `choices[].message.content`, and by short-circuiting tool-use requests in `LlmService.ToolUse.cs` with a `ToolCallNotSupportedException` so IBM deployment chat connections do not receive an incompatible OpenAI function-calling payload.
+- Document update: 2026-04-06 18:09 (KST) - Reworked message feedback toggles in `ChatWindow.MessageInteractions.cs`. `좋아요/싫어요` no longer keep separate local state with sibling reset callbacks; both buttons now derive from one shared `like/dislike/null` state and persist that single value back to the conversation/session.
+- Document update: 2026-04-06 18:09 (KST) - The feedback buttons now use the same glyph in both idle/active states and express activation through color plus rounded chip background/border, which avoids cases where the like filled-glyph was visually missing and ensures pressing `싫어요` again properly returns the message to an unselected state.