feat(用户服务): 添加故事服务Feign客户端熔断机制

添加StoryServiceClientFallback和StoryServiceClientFallbackFactory实现类，用于在故事服务不可用时提供默认值
配置feign.circuitbreaker.enabled=true启用熔断功能

timeline-user-service/src/main/java/com/timeline/user/feign/StoryServiceClient.java

@@ -8,7 +8,7 @@ import org.springframework.web.bind.annotation.RequestParam;
  * Story Service Feign Client
  * 用于调用 timeline-story-service 的接口
  */
-@FeignClient(name = "timeline-story-service", path = "/story")
+@FeignClient(name = "timeline-story-service", path = "/story", fallbackFactory = StoryServiceClientFallbackFactory.class)
 public interface StoryServiceClient {
 
     /**

timeline-user-service/src/main/java/com/timeline/user/feign/StoryServiceClientFallback.java

@@ -0,0 +1,31 @@
+package com.timeline.user.feign;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+
+/**
+ * StoryServiceClient Fallback
+ * 当 story-service 不可用时返回默认值
+ */
+@Slf4j
+@Component
+public class StoryServiceClientFallback implements StoryServiceClient {
+
+    @Override
+    public Long countStoriesByUserId(String userId) {
+        log.warn("StoryService 不可用，返回默认故事数量 0, userId={}", userId);
+        return 0L;
+    }
+
+    @Override
+    public Long countItemsByUserId(String userId) {
+        log.warn("StoryService 不可用，返回默认照片/视频数量 0, userId={}", userId);
+        return 0L;
+    }
+
+    @Override
+    public Long getTotalStorageByUserId(String userId) {
+        log.warn("StoryService 不可用，返回默认存储使用量 0, userId={}", userId);
+        return 0L;
+    }
+}

timeline-user-service/src/main/java/com/timeline/user/feign/StoryServiceClientFallbackFactory.java

@@ -0,0 +1,26 @@
+package com.timeline.user.feign;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.cloud.openfeign.FallbackFactory;
+import org.springframework.stereotype.Component;
+
+/**
+ * StoryServiceClient Fallback Factory
+ * 用于创建 Fallback 实例并记录异常原因
+ */
+@Slf4j
+@Component
+public class StoryServiceClientFallbackFactory implements FallbackFactory<StoryServiceClient> {
+
+    private final StoryServiceClientFallback fallback;
+
+    public StoryServiceClientFallbackFactory(StoryServiceClientFallback fallback) {
+        this.fallback = fallback;
+    }
+
+    @Override
+    public StoryServiceClient create(Throwable cause) {
+        log.error("StoryServiceClient 调用失败，使用 Fallback 处理", cause);
+        return fallback;
+    }
+}

timeline-user-service/src/main/resources/application.properties

@@ -53,10 +53,13 @@ server.servlet.encoding.force=true
 spring.datasource.hikari.maximum-pool-size=10
 spring.datasource.hikari.minimum-idle=2
 # 5 minutes
-spring.datasource.hikari.idle-timeout=300000        
+spring.datasource.hikari.idle-timeout=300000
 # 30 minutes, below MySQL wait_timeout
-spring.datasource.hikari.max-lifetime=1800000       
+spring.datasource.hikari.max-lifetime=1800000
 # wait up to 30s for a connection
-spring.datasource.hikari.connection-timeout=30000   
-spring.datasource.hikari.keepalive-time=0           
-spring.datasource.hikari.validation-timeout=5000
+spring.datasource.hikari.connection-timeout=30000
+spring.datasource.hikari.keepalive-time=0
+spring.datasource.hikari.validation-timeout=5000
+
+# Feign Client Configuration
+feign.circuitbreaker.enabled=true