feat(trace): improve session workbench review

src/main/java/com/superbiz/agent/controller/FaviconController.java

@@ -0,0 +1,19 @@
+package com.superbiz.agent.controller;
+
+import org.springframework.http.CacheControl;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.GetMapping;
+
+import java.time.Duration;
+
+@Controller
+public class FaviconController {
+
+    @GetMapping("/favicon.ico")
+    public ResponseEntity<Void> favicon() {
+        return ResponseEntity.noContent()
+                .cacheControl(CacheControl.maxAge(Duration.ofDays(1)))
+                .build();
+    }
+}

src/main/java/com/superbiz/agent/repository/AgentStepRepository.java

@@ -17,6 +17,11 @@ public interface AgentStepRepository extends JpaRepository<AgentStep, Long> {
      */
     List<AgentStep> findBySessionIdOrderByStepIndex(String sessionId);
 
+    /**
+     * 根据会话ID查询所有步骤，调用方负责按具体视图语义排序。
+     */
+    List<AgentStep> findBySessionId(String sessionId);
+
     /**
      * 统计某个会话的步骤数
      */

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

@@ -13,6 +13,7 @@ import com.superbiz.agent.repository.ToolInvocationRepository;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
 
+import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 
@@ -31,7 +32,7 @@ public class DiagnosisTraceService {
     public DiagnosisTraceResponse getTrace(String sessionId) {
         DiagnosisSession session = diagnosisSessionRepository.findBySessionId(sessionId)
                 .orElseThrow(() -> new SessionNotFoundException(sessionId));
-        List<AgentStep> steps = agentStepRepository.findBySessionIdOrderByStepIndex(sessionId);
+        List<AgentStep> steps = orderStepsForTrace(agentStepRepository.findBySessionId(sessionId));
         List<ToolInvocation> toolInvocations = toolInvocationRepository.findBySessionIdOrderByIdAsc(sessionId);
 
         return DiagnosisTraceResponse.builder()
@@ -42,6 +43,15 @@ public class DiagnosisTraceService {
                 .build();
     }
 
+    private List<AgentStep> orderStepsForTrace(List<AgentStep> steps) {
+        return steps.stream()
+                .sorted(Comparator
+                        .comparing(AgentStep::getCreatedAt, Comparator.nullsLast(Comparator.naturalOrder()))
+                        .thenComparing(AgentStep::getId, Comparator.nullsLast(Comparator.naturalOrder()))
+                        .thenComparing(AgentStep::getStepIndex, Comparator.nullsLast(Comparator.naturalOrder())))
+                .toList();
+    }
+
     private DiagnosisTraceResponse.SessionTrace toSessionTrace(DiagnosisSession session) {
         return DiagnosisTraceResponse.SessionTrace.builder()
                 .id(session.getId())