feat: 增强HIF轮询逻辑，添加退避饱和状态处理，优化日志记录

internal/deepseek/hif/hif.go

@@ -75,6 +75,9 @@ func (p *HIFPoller) GetHeaders() map[string]string {
 
 func (p *HIFPoller) pollLoop(kind, url string) {
 	interval := initialInterval
+	// saturated 标记退避是否已达到 maxInterval。达到后持续重试但降级日志，
+	// 避免在长期不可达环境（如 HF Spaces 无 IPv6 出口）刷屏；一旦成功即重置。
+	saturated := false
 	for {
 		select {
 		case <-p.stopCh:
@@ -84,15 +87,20 @@ func (p *HIFPoller) pollLoop(kind, url string) {
 
 		value, ttl, err := p.query(url)
 		if err != nil {
-			config.Logger.Warn("[hif] query failed", "kind", kind, "error", err, "retry_after", interval)
+			if saturated {
+				config.Logger.Debug("[hif] query failed (backoff saturated, retrying quietly)", "kind", kind, "error", err, "retry_after", interval)
+			} else {
+				config.Logger.Warn("[hif] query failed", "kind", kind, "error", err, "retry_after", interval)
+			}
 			select {
 			case <-p.stopCh:
 				return
 			case <-time.After(interval):
 			}
 			interval = time.Duration(float64(interval) * float64(backoffFactor))
-			if interval > maxInterval {
+			if interval >= maxInterval {
 				interval = maxInterval
+				saturated = true
 			}
 			continue
 		}
@@ -107,7 +115,12 @@ func (p *HIFPoller) pollLoop(kind, url string) {
 		}
 		p.mu.Unlock()
 
-		config.Logger.Info("[hif] query success", "kind", kind, "ttl", ttl)
+		if saturated {
+			config.Logger.Info("[hif] query recovered after backoff saturation", "kind", kind, "ttl", ttl)
+			saturated = false
+		} else {
+			config.Logger.Info("[hif] query success", "kind", kind, "ttl", ttl)
+		}
 		interval = initialInterval
 
 		sleepDuration := time.Duration(ttl) * time.Second