feat: 自动备份与保留策略、健康持续化与状态页、指标历史与趋势图，并修隧道判定误报与仪表盘布局（v1.2.11）

- 自动备份：每日一份（按最新备份是否在 24h 内判定，重启不重复）、保留份数可配、列表/下载/恢复/删除，恢复前先校验归档；顺手修 writeArchive 逐个检查 tar/gzip/文件 Close()（审查报告 §二）

- 健康持续化：只存状态变更（up/down/unknown）并推导可用率与不可用区间；公开状态页默认关闭、访问码存 SHA-256、按 IP 限流、只暴露域名与可用率

- 隧道判定修复：RouteHealthCandidate 新增 tunnel_known，frps 管理接口不可用时不再把「判不出来」当成「不通」（此前会误报「隧道连续不通」）；汇总与徽标同样区分「无法判定」

- 指标历史：metrics_samples 纵向点表（本机 CPU/内存/磁盘 + 每规则上下行，30 天保留、查询按桶平均、不做降采样表）；仪表盘趋势卡支持 1h/24h/7d

- 仪表盘布局：运行状态并入顶部统计区（运行时长补进「服务」卡）；性能并入系统资源那一行，整行 4 列

- 测试：backup/metrics/frp/api/app 新增用例；gofmt、go build/vet/test、vue-tsc、vite build 全绿

- agent 无改动，AgentVersion 保持 0.12.2

internal/frp/route_health_store.go

@@ -0,0 +1,85 @@
+package frp
+
+import (
+	"context"
+	"database/sql"
+	"time"
+)
+
+// latestRouteHealthStates 取每条规则最新一条记录的状态，用于「同状态不重复写」判断
+func (s *Store) latestRouteHealthStates(ctx context.Context) (map[string]string, error) {
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT e.server_id, e.domain, e.state
+		FROM route_health_events e
+		JOIN (
+			SELECT server_id, domain, MAX(id) AS id
+			FROM route_health_events
+			GROUP BY server_id, domain
+		) m ON m.id = e.id`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	states := map[string]string{}
+	for rows.Next() {
+		var (
+			serverID int64
+			domain   string
+			state    string
+		)
+		if err := rows.Scan(&serverID, &domain, &state); err != nil {
+			return nil, err
+		}
+		states[routeHealthKey(serverID, domain)] = state
+	}
+	return states, rows.Err()
+}
+
+// routeHealthEventsSince 取窗口内的变更，外加每条规则在窗口开始前的最后一条
+// ——否则「窗口开始时是什么状态」就无从得知了。
+func (s *Store) routeHealthEventsSince(ctx context.Context, since time.Time) ([]RouteHealthEvent, error) {
+	stamp := since.UTC().Format(time.RFC3339)
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT server_id, domain, state, COALESCE(reason, ''), COALESCE(detail, ''), at
+		FROM route_health_events WHERE at >= ?
+		UNION ALL
+		SELECT e.server_id, e.domain, e.state, COALESCE(e.reason, ''), COALESCE(e.detail, ''), e.at
+		FROM route_health_events e
+		JOIN (
+			SELECT server_id, domain, MAX(id) AS id
+			FROM route_health_events WHERE at < ?
+			GROUP BY server_id, domain
+		) m ON m.id = e.id`, stamp, stamp)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	events := make([]RouteHealthEvent, 0, 32)
+	for rows.Next() {
+		var event RouteHealthEvent
+		if err := rows.Scan(&event.ServerID, &event.Domain, &event.State, &event.Reason, &event.Detail, &event.At); err != nil {
+			return nil, err
+		}
+		events = append(events, event)
+	}
+	return events, rows.Err()
+}
+
+// pruneRouteHealthEvents 清理 before 之前的记录，返回删除条数
+func (s *Store) pruneRouteHealthEvents(ctx context.Context, before time.Time) (int64, error) {
+	res, err := s.db.ExecContext(ctx,
+		`DELETE FROM route_health_events WHERE at < ?`, before.UTC().Format(time.RFC3339))
+	if err != nil {
+		return 0, err
+	}
+	affected, err := res.RowsAffected()
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return 0, nil
+		}
+		return 0, err
+	}
+	return affected, nil
+}