feat(rate-limits): use 5m trend buckets and 24h/7d ranges

Overview API accepts bucket_minutes (5|60); rate-limit analysis uses
5-minute buckets and drops 15d/30d presets. Widen rank value column.

internal/apps/openflare/observability/routers.go

@@ -22,6 +22,7 @@ import (
 // @Param host query string false "请求 Host（单域名）"
 // @Param hosts query []string false "请求 Host 列表（多域名精确匹配）"
 // @Param hours query int false "统计时间范围（小时）"
+// @Param bucket_minutes query int false "趋势桶分钟数（5 或 60，默认 60）"
 // @Success 200 {object} response.Any{data=observability.AccessLogOverview} "访问日志概览"
 // @Failure 400 {object} response.Any "参数错误"
 // @Failure 401 {object} response.Any "未登录"
@@ -30,10 +31,11 @@ import (
 // @Router /api/v1/d/access-logs/overview [get]
 func GetAccessLogOverviewHandler(c *gin.Context) {
 	result, err := GetAccessLogOverview(c.Request.Context(), AccessLogOverviewQuery{
-		NodeID: c.Query("node_id"),
-		Host:   c.Query("host"),
-		Hosts:  readQueryStringArray(c, "hosts"),
-		Hours:  readQueryInt(c, "hours"),
+		NodeID:        c.Query("node_id"),
+		Host:          c.Query("host"),
+		Hosts:         readQueryStringArray(c, "hosts"),
+		Hours:         readQueryInt(c, "hours"),
+		BucketMinutes: readQueryInt(c, "bucket_minutes"),
 	})
 	if apiutil.AbortBadRequestOnError(c, err) {
 		return