perf: 六项性能优化

- DNS 解析缓存：sync.Map 缓存避免重复系统调用
- 凭据测试 TCP 预检：不可达目标直接跳过全部凭据
- Web 探测 HTTP Client 复用：全局共享连接池
- 端口扫描 Bloom Filter 去重：替代 map 降低内存
- 进度条 atomic 累加 + 50ms 节流渲染：消除锁竞争
- 服务探针预解码：Init 时预编译，运行时零解码开销

common/dns_cache.go

@@ -0,0 +1,27 @@
+package common
+
+import (
+	"net"
+	"sync"
+)
+
+// DNSCache 并发安全的 DNS 解析缓存
+// 对纯 IP 输入零开销（直接返回），对域名避免重复系统调用
+var DNSCache = &dnsCache{}
+
+type dnsCache struct {
+	m sync.Map // host -> *net.IPAddr
+}
+
+// ResolveIP 解析 host 为 *net.IPAddr，结果缓存
+func (c *dnsCache) ResolveIP(host string) (*net.IPAddr, error) {
+	if v, ok := c.m.Load(host); ok {
+		return v.(*net.IPAddr), nil
+	}
+	addr, err := net.ResolveIPAddr("ip", host)
+	if err != nil {
+		return nil, err
+	}
+	c.m.Store(host, addr)
+	return addr, nil
+}

common/progress_manager.go

@@ -143,16 +143,24 @@ func (pm *ProgressManager) UpdateProgress(increment int64) {
 		return
 	}
 
-	pm.mu.Lock()
-	defer pm.mu.Unlock()
-
-	pm.current += increment
-	if pm.current > pm.total {
-		pm.current = pm.total
+	// 原子累加，避免高并发下的锁竞争
+	newCurrent := atomic.AddInt64(&pm.current, increment)
+	if newCurrent > pm.total {
+		atomic.StoreInt64(&pm.current, pm.total)
 	}
 
-	// 更新活跃时间
-	pm.lastActivity = time.Now()
+	// 节流渲染：距上次渲染不足 50ms 则跳过
+	now := time.Now()
+	pm.mu.RLock()
+	lastAct := pm.lastActivity
+	pm.mu.RUnlock()
+	if now.Sub(lastAct) < 50*time.Millisecond {
+		return
+	}
+
+	pm.mu.Lock()
+	pm.lastActivity = now
+	pm.mu.Unlock()
 
 	pm.renderProgress()
 }
@@ -170,7 +178,7 @@ func (pm *ProgressManager) FinishProgress() {
 	pm.mu.Lock()
 	defer pm.mu.Unlock()
 
-	pm.current = pm.total
+	atomic.StoreInt64(&pm.current, pm.total)
 	pm.renderProgress()
 
 	// 停止活跃指示器
@@ -220,11 +228,12 @@ func (pm *ProgressManager) generateProgressBar() string {
 		return base
 	}
 
-	percentage := float64(pm.current) / float64(pm.total) * 100
+	percentage := float64(atomic.LoadInt64(&pm.current)) / float64(pm.total) * 100
 	elapsed := time.Since(pm.startTime)
+	current := atomic.LoadInt64(&pm.current)
 
 	// 计算速度
-	speed := float64(pm.current) / elapsed.Seconds()
+	speed := float64(current) / elapsed.Seconds()
 	speedStr := ""
 	if speed > 0 {
 		speedStr = fmt.Sprintf(" %.0f/s", speed)
@@ -232,8 +241,8 @@ func (pm *ProgressManager) generateProgressBar() string {
 
 	// 计算预估剩余时间
 	var eta string
-	if pm.current > 0 && pm.current < pm.total {
-		totalTime := elapsed * time.Duration(pm.total) / time.Duration(pm.current)
+	if current > 0 && current < pm.total {
+		totalTime := elapsed * time.Duration(pm.total) / time.Duration(current)
 		remaining := totalTime - elapsed
 		if remaining > 0 {
 			eta = fmt.Sprintf(" ETA:%s", formatDuration(remaining))
@@ -245,7 +254,7 @@ func (pm *ProgressManager) generateProgressBar() string {
 
 	// 计算固定部分的宽度
 	fixedPart := fmt.Sprintf("%s %s %5.1f%% [] (%d/%d)%s%s %s",
-		pm.description, spinner, percentage, pm.current, pm.total, speedStr, eta, packetInfo)
+		pm.description, spinner, percentage, current, pm.total, speedStr, eta, packetInfo)
 	fixedWidth := displayWidth(fixedPart)
 
 	// 计算进度条槽位可用宽度（预留2字符余量）
@@ -272,7 +281,7 @@ func (pm *ProgressManager) generateProgressBar() string {
 
 	// 构建最终进度条
 	result := fmt.Sprintf("%s %s %5.1f%% %s (%d/%d)%s%s",
-		pm.description, spinner, percentage, bar, pm.current, pm.total, speedStr, eta)
+		pm.description, spinner, percentage, bar, current, pm.total, speedStr, eta)
 
 	if packetInfo != "" {
 		result += " " + packetInfo
@@ -470,7 +479,7 @@ func (pm *ProgressManager) GetPercent() float64 {
 	if !pm.isActive || pm.total == 0 {
 		return 0
 	}
-	return float64(pm.current) / float64(pm.total) * 100
+	return float64(atomic.LoadInt64(&pm.current)) / float64(pm.total) * 100
 }
 
 // =============================================================================
@@ -512,7 +521,7 @@ func (pm *ProgressManager) renderProgressUnsafe() {
 	// 计算当前百分比（避免除零）
 	currentPercent := 0
 	if pm.total > 0 {
-		currentPercent = int((pm.current * 100) / pm.total)
+		currentPercent = int((atomic.LoadInt64(&pm.current) * 100) / pm.total)
 	}
 
 	// 只在百分比变化时更新，减少不必要的渲染