🐛 fix(server): 增加优雅退出与请求超时保护

- 新增 SIGINT/SIGTERM 信号处理与 http.Server.Shutdown,退出前确保统计数据保存、数据库正常关闭
- 为 http.Server 设置 ReadHeaderTimeout/ReadTimeout/WriteTimeout/IdleTimeout,防止慢客户端长期占用连接
- 全局配置指针改为 atomic.Pointer 并提供 GetAppConfig 访问器,消除配置热更新时的数据竞争,同时删除冗余的 manager.config 字段
- 请求统计九组计数器重构为 map[string]*atomic.Int64,统一 incrementStat/getStatsSnapshot 访问,精简约 40 行样板代码
- go mod tidy 清理 go.mod 与 go.sum 中的冗余依赖条目

internal/handlers/common.go

@@ -13,42 +13,41 @@ import (
 var (
 	startTime    = time.Now()
 	deviceHeader string
-	
+
 	// 请求统计
-	totalRequests     int64
-	searchRequests    int64
-	detailRequests    int64
-	catalogRequests   int64
-	contentRequests   int64
-	mangaRequests     int64
-	audioRequests     int64
-	videoRequests     int64
-	categoryRequests  int64
-	
+	requestStats = newRequestStats()
+
 	// 统计保存定时器
 	statsSaveTicker *time.Ticker
 )
 
-// 统计函数
-func incrementTotal()    { atomic.AddInt64(&totalRequests, 1) }
-func incrementSearch()   { atomic.AddInt64(&searchRequests, 1) }
-func incrementDetail()   { atomic.AddInt64(&detailRequests, 1) }
-func incrementCatalog()  { atomic.AddInt64(&catalogRequests, 1) }
-func incrementContent()  { atomic.AddInt64(&contentRequests, 1) }
-func incrementManga()    { atomic.AddInt64(&mangaRequests, 1) }
-func incrementAudio()    { atomic.AddInt64(&audioRequests, 1) }
-func incrementVideo()    { atomic.AddInt64(&videoRequests, 1) }
-func incrementCategory() { atomic.AddInt64(&categoryRequests, 1) }
+// statsKinds 统计类别
+var statsKinds = []string{"total", "search", "detail", "catalog", "content", "manga", "audio", "video", "category"}
 
-func getTotal() int64    { return atomic.LoadInt64(&totalRequests) }
-func getSearch() int64   { return atomic.LoadInt64(&searchRequests) }
-func getDetail() int64   { return atomic.LoadInt64(&detailRequests) }
-func getCatalog() int64  { return atomic.LoadInt64(&catalogRequests) }
-func getContent() int64  { return atomic.LoadInt64(&contentRequests) }
-func getManga() int64    { return atomic.LoadInt64(&mangaRequests) }
-func getAudio() int64    { return atomic.LoadInt64(&audioRequests) }
-func getVideo() int64    { return atomic.LoadInt64(&videoRequests) }
-func getCategory() int64 { return atomic.LoadInt64(&categoryRequests) }
+// newRequestStats 初始化各类计数器
+func newRequestStats() map[string]*atomic.Int64 {
+	m := make(map[string]*atomic.Int64, len(statsKinds))
+	for _, k := range statsKinds {
+		m[k] = &atomic.Int64{}
+	}
+	return m
+}
+
+// incrementStat 原子递增请求计数
+func incrementStat(kinds ...string) {
+	for _, k := range kinds {
+		requestStats[k].Add(1)
+	}
+}
+
+// getStatsSnapshot 获取所有计数器的快照
+func getStatsSnapshot() map[string]int64 {
+	snapshot := make(map[string]int64, len(requestStats))
+	for k, c := range requestStats {
+		snapshot[k] = c.Load()
+	}
+	return snapshot
+}
 
 // SetDeviceHeader 设置设备header
 func SetDeviceHeader(header string) {
@@ -63,32 +62,16 @@ func LoadStatistics() {
 		return
 	}
 	
-	atomic.StoreInt64(&totalRequests, stats["total"])
-	atomic.StoreInt64(&searchRequests, stats["search"])
-	atomic.StoreInt64(&detailRequests, stats["detail"])
-	atomic.StoreInt64(&catalogRequests, stats["catalog"])
-	atomic.StoreInt64(&contentRequests, stats["content"])
-	atomic.StoreInt64(&mangaRequests, stats["manga"])
-	atomic.StoreInt64(&audioRequests, stats["audio"])
-	atomic.StoreInt64(&videoRequests, stats["video"])
-	atomic.StoreInt64(&categoryRequests, stats["category"])
+	for k, v := range stats {
+		if c, ok := requestStats[k]; ok {
+			c.Store(v)
+		}
+	}
 }
 
 // SaveStatistics 保存统计数据到数据库
 func SaveStatistics() {
-	stats := map[string]int64{
-		"total":    atomic.LoadInt64(&totalRequests),
-		"search":   atomic.LoadInt64(&searchRequests),
-		"detail":   atomic.LoadInt64(&detailRequests),
-		"catalog":  atomic.LoadInt64(&catalogRequests),
-		"content":  atomic.LoadInt64(&contentRequests),
-		"manga":    atomic.LoadInt64(&mangaRequests),
-		"audio":    atomic.LoadInt64(&audioRequests),
-		"video":    atomic.LoadInt64(&videoRequests),
-		"category": atomic.LoadInt64(&categoryRequests),
-	}
-	
-	if err := fqapi.SaveStatistics(stats); err != nil {
+	if err := fqapi.SaveStatistics(getStatsSnapshot()); err != nil {
 		fmt.Printf("保存统计数据失败: %v\n", err)
 	}
 }