fix(discord_bot): unified prompt JSON '{' parsing fallback

api/discord_bot.py

@@ -183,6 +183,18 @@ def _parse_unified_response(raw: str) -> dict:
                     except json.JSONDecodeError:
                         break
 
+    # 2.5) JSON 시작 중괄호 누락 복구
+    raw_s = raw.strip()
+    if raw_s.startswith('"mode"'):
+        if not raw_s.startswith("{"):
+            raw_s = "{" + raw_s
+        if not raw_s.endswith("}"):
+            raw_s = raw_s + "}"
+        try:
+            return json.loads(raw_s, strict=False)
+        except json.JSONDecodeError:
+            pass
+
     # 3) 파싱 실패 → chat 모드 폴백
     logger.warning(f"unified 응답 JSON 파싱 실패: {raw[:200]}")
     return {"mode": "chat", "response": raw}