feat(rag): modularize knowledge retrieval pipeline

src/main/java/com/superbiz/agent/domain/model/SessionContext.java

@@ -1,5 +1,7 @@
 package com.superbiz.agent.domain.model;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -20,6 +22,7 @@ import java.util.Map;
 @Builder
 @NoArgsConstructor
 @AllArgsConstructor
+@JsonIgnoreProperties(ignoreUnknown = true)
 public class SessionContext implements Serializable {
 
     private static final long serialVersionUID = 1L;
@@ -118,6 +121,7 @@ public class SessionContext implements Serializable {
     /**
      * 获取聊天历史副本，避免调用方直接修改内部列表。
      */
+    @JsonIgnore
     public List<Map<String, String>> getMessageHistorySnapshot() {
         if (this.messageHistory == null || this.messageHistory.isEmpty()) {
             return new ArrayList<>();
@@ -141,6 +145,7 @@ public class SessionContext implements Serializable {
         this.lastActiveAt = LocalDateTime.now();
     }
 
+    @JsonIgnore
     public int getMessagePairCount() {
         return this.messageHistory == null ? 0 : this.messageHistory.size() / 2;
     }