feat: add rag evidence postprocess blocks

src/main/java/com/superbiz/agent/dto/EvidenceBlock.java

@@ -0,0 +1,28 @@
+package com.superbiz.agent.dto;
+
+import lombok.Builder;
+import lombok.Data;
+
+import java.util.List;
+
+/**
+ * Structured evidence returned by knowledge retrieval.
+ */
+@Data
+@Builder
+public class EvidenceBlock {
+
+    private String source;
+
+    private String title;
+
+    private String breadcrumb;
+
+    private String retrievalLayer;
+
+    private String content;
+
+    private Double score;
+
+    private List<String> hitReasons;
+}

src/main/java/com/superbiz/agent/dto/LookupResult.java

@@ -27,6 +27,21 @@ public class LookupResult {
      */
     private SupplementResult supplement;
 
+    /**
+     * Structured evidence blocks after retrieval post-processing.
+     */
+    private List<EvidenceBlock> evidenceBlocks;
+
+    /**
+     * Candidate count before evidence deduplication.
+     */
+    private Integer evidenceCandidateCount;
+
+    /**
+     * Evidence block count after post-processing.
+     */
+    private Integer evidenceBlockCount;
+
     /**
      * 归一化质量等级：PRECISE / HIGHLY_RELEVANT / REFERENCE
      */