fix: 修复ContextInterceptor响应头未设置traceId和spanId的问题

- 新增HEADER_SPAN_ID常量
- preHandle中生成SpanId并设置到响应头
- response.setHeader(HEADER_TRACE_ID, traceId)
- response.setHeader(HEADER_SPAN_ID, spanId)

fund-common/src/main/java/com/fundplatform/common/web/ContextInterceptor.java

@@ -14,7 +14,7 @@ import org.springframework.web.servlet.HandlerInterceptor;
 /**
  * 租户和用户上下文拦截器
  * 从HTTP Header中提取租户ID、用户ID、请求来源等信息，设置到ThreadLocal中
- * 同时记录请求来源和链路耗时信息
+ * 同时记录请求来源和链路耗时信息，并在响应头中返回traceId和spanId
  */
 @Component
 public class ContextInterceptor implements HandlerInterceptor {
@@ -26,6 +26,7 @@ public class ContextInterceptor implements HandlerInterceptor {
     public static final String HEADER_TENANT_ID = "X-Tenant-Id";
     public static final String HEADER_USER_ID = "X-User-Id";
     public static final String HEADER_TRACE_ID = "X-Trace-Id";
+    public static final String HEADER_SPAN_ID = "X-Span-Id";
 
     /**
      * 请求开始时间属性Key
@@ -80,19 +81,31 @@ public class ContextInterceptor implements HandlerInterceptor {
             }
         }
 
-        // 提取 TraceId（如不存在，后续会在需要时自动生成）
+        // 提取或生成 TraceId（全链路唯一标识）
         String traceId = request.getHeader(HEADER_TRACE_ID);
         if (traceId != null && !traceId.isEmpty()) {
             TraceContextHolder.setTraceId(traceId);
+        } else {
+            traceId = TraceContextHolder.getOrCreateTraceId();
         }
 
-        // 记录请求追踪日志
+        // 生成 SpanId（当前服务处理标识，每个请求唯一）
+        String spanId = TraceContextHolder.getOrCreateSpanId();
+
+        // 在响应头中返回 traceId 和 spanId，方便客户端追踪
+        response.setHeader(HEADER_TRACE_ID, traceId);
+        response.setHeader(HEADER_SPAN_ID, spanId);
+
+        // 记录请求追踪日志（使用spanId作为索引ID）
         if (sourceService != null && chainDuration != null) {
-            logger.info("[Trace] {} -> {} | traceId={} | chainTime={}ms | path={}",
+            logger.info("[{}] {} -> {} | traceId={} | chainTime={}ms | path={}",
-                    sourceService, serviceName, traceId, chainDuration, request.getRequestURI());
+                    spanId, sourceService, serviceName, traceId, chainDuration, request.getRequestURI());
         } else if (sourceService != null) {
-            logger.info("[Trace] {} -> {} | traceId={} | path={}",
+            logger.info("[{}] {} -> {} | traceId={} | path={}",
-                    sourceService, serviceName, traceId, request.getRequestURI());
+                    spanId, sourceService, serviceName, traceId, request.getRequestURI());
+        } else {
+            logger.info("[{}] external -> {} | traceId={} | path={}",
+                    spanId, serviceName, traceId, request.getRequestURI());
         }
 
         return true;
@@ -103,12 +116,15 @@ public class ContextInterceptor implements HandlerInterceptor {
                                  Object handler, Exception ex) {
         // 计算当前服务处理耗时
         Long startTime = (Long) request.getAttribute(ATTR_START_TIME);
+        String spanId = TraceContextHolder.getSpanId();
+        String traceId = TraceContextHolder.getTraceId();
+        String sourceService = request.getHeader(HEADER_SOURCE_SERVICE);
+        
         if (startTime != null) {
             long duration = System.currentTimeMillis() - startTime;
-            String traceId = request.getHeader(HEADER_TRACE_ID);
-            String sourceService = request.getHeader(HEADER_SOURCE_SERVICE);
             
-            logger.debug("[Trace] {} -> {} | traceId={} | processTime={}ms | status={}",
+            logger.debug("[{}] {} -> {} | traceId={} | processTime={}ms | status={}",
+                    spanId != null ? spanId : "unknown",
                     sourceService != null ? sourceService : "external",
                     serviceName,
                     traceId,