feat(agent): add executor evidence v2 contract

src/main/java/com/superbiz/agent/service/ChatService.java

@@ -444,8 +444,12 @@ public class ChatService {
                 }
 
                 if ("PASS".equals(finalDecision.verdict())) {
-                    answer = extractUserFacingAnswer(answer)
-                            .orElse(answer == null || answer.isBlank() ? "抱歉，多 Agent 分析未能生成有效结论。" : answer);
+                    String executorAnswer = answer;
+                    answer = extractUserFacingAnswer(executorAnswer)
+                            .or(() -> renderStructuredExecutorAnswer(executorAnswer))
+                            .orElse(executorAnswer == null || executorAnswer.isBlank()
+                                    ? "抱歉，多 Agent 分析未能生成有效结论。"
+                                    : executorAnswer);
                     persistVerifierEvaluation(session, finalDecision, round);
                     break;
                 }
@@ -816,6 +820,98 @@ public class ChatService {
         return Optional.empty();
     }
 
+    private Optional<String> renderStructuredExecutorAnswer(String executorAnswer) {
+        if (executorAnswer == null || executorAnswer.isBlank()) {
+            return Optional.empty();
+        }
+        try {
+            JsonNode root = objectMapper.readTree(sanitizeJsonPayload(executorAnswer));
+            if (!"executor_evidence_v2".equals(root.path("answer_version").asText(""))) {
+                return Optional.empty();
+            }
+
+            StringBuilder output = new StringBuilder();
+            appendTextArraySection(output, "已确认信息", root.path("claims"), "claim_text", "暂无可稳定确认的信息");
+            appendHypothesesSection(output, root.path("hypotheses"));
+            appendStringArraySection(output, "当前缺口", root.path("missing_info"), "当前缺少足够的直接证据支撑完整结论");
+            appendRecommendedActionsSection(output, root.path("recommended_actions"));
+            String rendered = output.toString().trim();
+            return rendered.isBlank() ? Optional.empty() : Optional.of(rendered);
+        } catch (Exception e) {
+            logger.debug("Failed to render executor_evidence_v2 answer", e);
+            return Optional.empty();
+        }
+    }
+
+    private void appendTextArraySection(StringBuilder output, String title, JsonNode items,
+                                        String fieldName, String emptyText) {
+        output.append(title).append("：");
+        if (!items.isArray() || items.isEmpty()) {
+            output.append("\n- ").append(emptyText);
+            return;
+        }
+        for (JsonNode item : items) {
+            String text = item.path(fieldName).asText("");
+            if (!text.isBlank()) {
+                output.append("\n- ").append(text);
+            }
+        }
+        if (output.charAt(output.length() - 1) == '：') {
+            output.append("\n- ").append(emptyText);
+        }
+    }
+
+    private void appendHypothesesSection(StringBuilder output, JsonNode hypotheses) {
+        if (!hypotheses.isArray() || hypotheses.isEmpty()) {
+            return;
+        }
+        output.append("\n\n可能方向：");
+        for (JsonNode hypothesis : hypotheses) {
+            String text = hypothesis.path("hypothesis_text").asText("");
+            if (text.isBlank()) {
+                continue;
+            }
+            String basis = hypothesis.path("basis").asText("");
+            output.append("\n- ").append(text);
+            if (!basis.isBlank()) {
+                output.append("（").append(basis).append("）");
+            }
+        }
+    }
+
+    private void appendStringArraySection(StringBuilder output, String title, JsonNode items, String emptyText) {
+        output.append("\n\n").append(title).append("：");
+        if (!items.isArray() || items.isEmpty()) {
+            output.append("\n- ").append(emptyText);
+            return;
+        }
+        for (JsonNode item : items) {
+            String text = item.asText("");
+            if (!text.isBlank()) {
+                output.append("\n- ").append(text);
+            }
+        }
+    }
+
+    private void appendRecommendedActionsSection(StringBuilder output, JsonNode actions) {
+        output.append("\n\n建议下一步：");
+        if (!actions.isArray() || actions.isEmpty()) {
+            output.append("\n- 围绕上述证据缺口补充只读查询，再由人工复核最终结论");
+            return;
+        }
+        for (JsonNode action : actions) {
+            String text = action.path("action_text").asText("");
+            if (text.isBlank()) {
+                continue;
+            }
+            String reason = action.path("reason").asText("");
+            output.append("\n- ").append(text);
+            if (!reason.isBlank()) {
+                output.append("：").append(reason);
+            }
+        }
+    }
+
     private String buildDegradedOutput(VerifierDecision decision) {
         StringBuilder output = new StringBuilder(DEGRADED_PREFIX);