feat(notify): 告警补服务端掉线/Agent 不可达/配置漂移，巡检改 Source 接口（v1.2.10）

- 三个新事件（默认关闭）：公网服务端掉线、公网 agent 不可达、配置漂移；连续失败阈值与漂移提醒间隔均可配，达标与恢复各报一次

- 避免误报：只在「用户要服务端运行」时判定掉线；ConnectionState=unknown 按健康处理；没配 agent 的服务端不参与可达性判定

- internal/monitor 改 Source 接口（Routes/Servers/Agents/Drift），frp 适配在 internal/app/monitor_source.go；「连续 N 次」抽成共用 failureTransition，通知一律在锁外调用

- 通知图标分类补齐；通知方式标签改「Webhook / IM 机器人」；新增 6 个设置项；补 serverDown/serverLabel/stateOr 测试

- agent 无改动，AgentVersion 保持 0.12.2

internal/notify/store.go

@@ -80,6 +80,9 @@ func (s *Store) load(ctx context.Context, decrypt bool) (Config, runtimeSecrets,
 	cfg.MemoryThreshold = intSetting(s.settings, ctx, settings.KeyNotifyMemoryThreshold, DefaultMemoryThreshold)
 	cfg.DiskThreshold = intSetting(s.settings, ctx, settings.KeyNotifyDiskThreshold, DefaultDiskThreshold)
 	cfg.TunnelFailThreshold = intSetting(s.settings, ctx, settings.KeyNotifyTunnelFailThreshold, DefaultTunnelFailThreshold)
+	cfg.FrpsFailThreshold = intSetting(s.settings, ctx, settings.KeyNotifyFrpsFailThreshold, DefaultFrpsFailThreshold)
+	cfg.AgentFailThreshold = intSetting(s.settings, ctx, settings.KeyNotifyAgentFailThreshold, DefaultAgentFailThreshold)
+	cfg.DriftCooldownHours = intSetting(s.settings, ctx, settings.KeyNotifyDriftCooldownHours, DefaultDriftCooldownHours)
 
 	if hasNotifyEventSettings(ctx, s.settings) {
 		cfg.OnDDNSIPChange = flag(s.settings, ctx, settings.KeyNotifyOnDDNSIPChange, true)
@@ -93,6 +96,9 @@ func (s *Store) load(ctx context.Context, decrypt bool) (Config, runtimeSecrets,
 		// 资源与隧道告警默认关闭：升级后不改变现有用户收到的通知
 		cfg.OnResourceThreshold = flag(s.settings, ctx, settings.KeyNotifyOnResourceThreshold, false)
 		cfg.OnTunnelDown = flag(s.settings, ctx, settings.KeyNotifyOnTunnelDown, false)
+		cfg.OnFrpsDown = flag(s.settings, ctx, settings.KeyNotifyOnFrpsDown, false)
+		cfg.OnAgentUnreachable = flag(s.settings, ctx, settings.KeyNotifyOnAgentUnreachable, false)
+		cfg.OnRouteDrift = flag(s.settings, ctx, settings.KeyNotifyOnRouteDrift, false)
 	} else {
 		legacyDDNS := flag(s.settings, ctx, settings.KeyNotifyOnDDNSError, true)
 		legacyCert := flag(s.settings, ctx, settings.KeyNotifyOnCertError, true)
@@ -193,6 +199,9 @@ func hasNotifyEventSettings(ctx context.Context, store *settings.Store) bool {
 		settings.KeyNotifyOnNginxReloadFailure,
 		settings.KeyNotifyOnResourceThreshold,
 		settings.KeyNotifyOnTunnelDown,
+		settings.KeyNotifyOnFrpsDown,
+		settings.KeyNotifyOnAgentUnreachable,
+		settings.KeyNotifyOnRouteDrift,
 	}
 	for _, key := range keys {
 		raw, err := store.Get(ctx, key)
@@ -253,6 +262,24 @@ func (s *Store) Save(ctx context.Context, in SaveInput) error {
 	if err := s.settings.SetInt(ctx, settings.KeyNotifyTunnelFailThreshold, clampThreshold(in.TunnelFailThreshold, DefaultTunnelFailThreshold)); err != nil {
 		return err
 	}
+	if err := s.settings.SetBool(ctx, settings.KeyNotifyOnFrpsDown, in.OnFrpsDown); err != nil {
+		return err
+	}
+	if err := s.settings.SetBool(ctx, settings.KeyNotifyOnAgentUnreachable, in.OnAgentUnreachable); err != nil {
+		return err
+	}
+	if err := s.settings.SetBool(ctx, settings.KeyNotifyOnRouteDrift, in.OnRouteDrift); err != nil {
+		return err
+	}
+	if err := s.settings.SetInt(ctx, settings.KeyNotifyFrpsFailThreshold, clampThreshold(in.FrpsFailThreshold, DefaultFrpsFailThreshold)); err != nil {
+		return err
+	}
+	if err := s.settings.SetInt(ctx, settings.KeyNotifyAgentFailThreshold, clampThreshold(in.AgentFailThreshold, DefaultAgentFailThreshold)); err != nil {
+		return err
+	}
+	if err := s.settings.SetInt(ctx, settings.KeyNotifyDriftCooldownHours, clampThreshold(in.DriftCooldownHours, DefaultDriftCooldownHours)); err != nil {
+		return err
+	}
 	threshold := in.IPFrequentThreshold
 	if threshold <= 0 {
 		threshold = DefaultIPFrequentThreshold
@@ -493,6 +520,12 @@ func ParseSaveInputFromMap(values map[string]string) (SaveInput, bool) {
 	in.MemoryThreshold = intSettingFromMap(values, settings.KeyNotifyMemoryThreshold, DefaultMemoryThreshold)
 	in.DiskThreshold = intSettingFromMap(values, settings.KeyNotifyDiskThreshold, DefaultDiskThreshold)
 	in.TunnelFailThreshold = intSettingFromMap(values, settings.KeyNotifyTunnelFailThreshold, DefaultTunnelFailThreshold)
+	in.OnFrpsDown = values[settings.KeyNotifyOnFrpsDown] == "1" || strings.EqualFold(values[settings.KeyNotifyOnFrpsDown], "true")
+	in.OnAgentUnreachable = values[settings.KeyNotifyOnAgentUnreachable] == "1" || strings.EqualFold(values[settings.KeyNotifyOnAgentUnreachable], "true")
+	in.OnRouteDrift = values[settings.KeyNotifyOnRouteDrift] == "1" || strings.EqualFold(values[settings.KeyNotifyOnRouteDrift], "true")
+	in.FrpsFailThreshold = intSettingFromMap(values, settings.KeyNotifyFrpsFailThreshold, DefaultFrpsFailThreshold)
+	in.AgentFailThreshold = intSettingFromMap(values, settings.KeyNotifyAgentFailThreshold, DefaultAgentFailThreshold)
+	in.DriftCooldownHours = intSettingFromMap(values, settings.KeyNotifyDriftCooldownHours, DefaultDriftCooldownHours)
 	return in, true
 }