perf(日志): 降噪优化，将常规成功日志降级为 Debug 级别

- GIN Logger 中间件跳过 /health 和 /setup/status 的请求日志
- UsageCleanup 空闲轮询（no_task）日志降级为 slog.Debug
- Scheduler 常规 rebuild ok 日志降级为 slog.Debug
- DashboardAggregation 常规聚合完成日志降级为 slog.Debug
- TokenRefresh 无刷新活动时周期日志降级为 slog.Debug

生产环境（Info 级别）下自动静默，debug 模式下仍可见。
错误、警告类日志保持原有级别不变。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/internal/server/middleware/logger.go

@@ -13,9 +13,17 @@ func Logger() gin.HandlerFunc {
 		// 开始时间
 		startTime := time.Now()
 
+		// 请求路径
+		path := c.Request.URL.Path
+
 		// 处理请求
 		c.Next()
 
+		// 跳过健康检查等高频探针路径的日志
+		if path == "/health" || path == "/setup/status" {
+			return
+		}
+
 		// 结束时间
 		endTime := time.Now()
 
@@ -25,9 +33,6 @@ func Logger() gin.HandlerFunc {
 		// 请求方法
 		method := c.Request.Method
 
-		// 请求路径
-		path := c.Request.URL.Path
-
 		// 状态码
 		statusCode := c.Writer.Status()
 

backend/internal/service/dashboard_aggregation_service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"log"
+	"log/slog"
 	"sync/atomic"
 	"time"
 
@@ -224,11 +225,11 @@ func (s *DashboardAggregationService) runScheduledAggregation() {
 	if updateErr != nil {
 		log.Printf("[DashboardAggregation] 更新水位失败: %v", updateErr)
 	}
-	log.Printf("[DashboardAggregation] 聚合完成 (start=%s end=%s duration=%s watermark_updated=%t)",
-		start.Format(time.RFC3339),
-		now.Format(time.RFC3339),
-		time.Since(jobStart).String(),
-		updateErr == nil,
+	slog.Debug("[DashboardAggregation] 聚合完成",
+		"start", start.Format(time.RFC3339),
+		"end", now.Format(time.RFC3339),
+		"duration", time.Since(jobStart).String(),
+		"watermark_updated", updateErr == nil,
 	)
 
 	s.maybeCleanupRetention(ctx, now)

backend/internal/service/scheduler_snapshot_service.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"log"
+	"log/slog"
 	"strconv"
 	"sync"
 	"time"
@@ -451,7 +452,7 @@ func (s *SchedulerSnapshotService) rebuildBucket(ctx context.Context, bucket Sch
 		log.Printf("[Scheduler] rebuild cache failed: bucket=%s reason=%s err=%v", bucket.String(), reason, err)
 		return err
 	}
-	log.Printf("[Scheduler] rebuild ok: bucket=%s reason=%s size=%d", bucket.String(), reason, len(accounts))
+	slog.Debug("[Scheduler] rebuild ok", "bucket", bucket.String(), "reason", reason, "size", len(accounts))
 	return nil
 }
 

backend/internal/service/token_refresh_service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"log/slog"
 	"strings"
 	"sync"
 	"time"
@@ -164,9 +165,15 @@ func (s *TokenRefreshService) processRefresh() {
 		}
 	}
 
-	// 始终打印周期日志，便于跟踪服务运行状态
-	log.Printf("[TokenRefresh] Cycle complete: total=%d, oauth=%d, needs_refresh=%d, refreshed=%d, failed=%d",
-		totalAccounts, oauthAccounts, needsRefresh, refreshed, failed)
+	// 无刷新活动时降级为 Debug，有实际刷新活动时保持 Info
+	if needsRefresh == 0 && failed == 0 {
+		slog.Debug("[TokenRefresh] Cycle complete",
+			"total", totalAccounts, "oauth", oauthAccounts,
+			"needs_refresh", needsRefresh, "refreshed", refreshed, "failed", failed)
+	} else {
+		log.Printf("[TokenRefresh] Cycle complete: total=%d, oauth=%d, needs_refresh=%d, refreshed=%d, failed=%d",
+			totalAccounts, oauthAccounts, needsRefresh, refreshed, failed)
+	}
 }
 
 // listActiveAccounts 获取所有active状态的账号

backend/internal/service/usage_cleanup_service.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"log/slog"
 	"net/http"
 	"strings"
 	"sync"
@@ -174,7 +175,7 @@ func (s *UsageCleanupService) runOnce() {
 		return
 	}
 	if task == nil {
-		log.Printf("[UsageCleanup] run_once done: no_task=true")
+		slog.Debug("[UsageCleanup] run_once done: no_task=true")
 		return
 	}