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/monitor/monitor_test.go

@@ -2,20 +2,20 @@ package monitor
 
 import "testing"
 
-func TestTunnelTransitionAlertsOncePerOutage(t *testing.T) {
+func TestFailureTransitionAlertsOncePerOutage(t *testing.T) {
 	const limit = 3
 	failures := 0
-	var events []tunnelEvent
+	var events []failureEvent
 
 	// 连续三轮不通：只在第 3 轮（刚好达到阈值）发一次
 	for i := 0; i < 5; i++ {
-		var event tunnelEvent
-		failures, event = tunnelTransition(failures, false, limit)
-		if event != tunnelEventNone {
+		var event failureEvent
+		failures, event = failureTransition(failures, false, limit)
+		if event != failureEventNone {
 			events = append(events, event)
 		}
 	}
-	if len(events) != 1 || events[0] != tunnelEventDown {
+	if len(events) != 1 || events[0] != failureEventDown {
 		t.Fatalf("连续不通应只告警一次，实际 %v", events)
 	}
 	if failures != 5 {
@@ -23,31 +23,31 @@ func TestTunnelTransitionAlertsOncePerOutage(t *testing.T) {
 	}
 
 	// 恢复：发一次恢复通知并清零
-	failures, event := tunnelTransition(failures, true, limit)
-	if event != tunnelEventRecovered || failures != 0 {
+	failures, event := failureTransition(failures, true, limit)
+	if event != failureEventRecovered || failures != 0 {
 		t.Fatalf("恢复应通知一次并清零：event=%v failures=%d", event, failures)
 	}
 
 	// 恢复后再次不通：还能再报一次
-	failures, event = tunnelTransition(failures, false, limit)
-	if event != tunnelEventNone || failures != 1 {
+	failures, event = failureTransition(failures, false, limit)
+	if event != failureEventNone || failures != 1 {
 		t.Fatalf("恢复后重新计数：event=%v failures=%d", event, failures)
 	}
-	failures, event = tunnelTransition(failures, false, limit)
-	if event != tunnelEventNone {
+	failures, event = failureTransition(failures, false, limit)
+	if event != failureEventNone {
 		t.Fatalf("未达阈值不应告警：%v", event)
 	}
-	if _, event = tunnelTransition(failures, false, limit); event != tunnelEventDown {
+	if _, event = failureTransition(failures, false, limit); event != failureEventDown {
 		t.Fatalf("第二次中断达到阈值应再告警一次：%v", event)
 	}
 }
 
-func TestTunnelTransitionBelowThresholdIsSilent(t *testing.T) {
+func TestFailureTransitionBelowThresholdIsSilent(t *testing.T) {
 	// 单次抖动（未达阈值）不打扰用户，也不算作恢复
-	if failures, event := tunnelTransition(0, true, 3); failures != 0 || event != tunnelEventNone {
+	if failures, event := failureTransition(0, true, 3); failures != 0 || event != failureEventNone {
 		t.Fatalf("健康状态不应产生事件：%d %v", failures, event)
 	}
-	if failures, event := tunnelTransition(1, true, 3); failures != 0 || event != tunnelEventNone {
+	if failures, event := failureTransition(1, true, 3); failures != 0 || event != failureEventNone {
 		t.Fatalf("未达阈值的恢复不应通知：%d %v", failures, event)
 	}
 }
@@ -69,3 +69,41 @@ func TestDetailOrFallsBack(t *testing.T) {
 		t.Fatalf("非空详情应原样返回，实际 %q", got)
 	}
 }
+
+func TestServerDownOnlyWhenUserWantsItRunning(t *testing.T) {
+	// 用户手动停掉的不算掉线
+	stopped := ServerStatus{DesiredState: "stopped", ProcessState: "stopped", ConnectionState: "disconnected"}
+	if serverDown(stopped) {
+		t.Fatal("用户手动停止的服务端不应判为掉线")
+	}
+	// 期望运行但进程没在跑
+	if !serverDown(ServerStatus{DesiredState: "running", ProcessState: "stopped"}) {
+		t.Fatal("期望运行但进程未运行应判为掉线")
+	}
+	// 进程在跑但连不上 frps
+	if !serverDown(ServerStatus{DesiredState: "running", ProcessState: "running", ConnectionState: "disconnected"}) {
+		t.Fatal("连接断开应判为掉线")
+	}
+	// 状态源读不到连接状态时不报警：manager+log 偶尔读不到不代表掉线
+	if serverDown(ServerStatus{DesiredState: "running", ProcessState: "running", ConnectionState: "unknown"}) {
+		t.Fatal("连接状态未知时不应误报")
+	}
+}
+
+func TestServerLabelFallsBackToID(t *testing.T) {
+	if got := serverLabel(3, "   "); got != "服务端 #3" {
+		t.Fatalf("无名服务端应回落到编号，实际 %q", got)
+	}
+	if got := serverLabel(3, "VPS-香港"); got != "VPS-香港" {
+		t.Fatalf("有名字应直接用名字，实际 %q", got)
+	}
+}
+
+func TestStateOrFallsBackToPlaceholder(t *testing.T) {
+	if got := stateOr(""); got != "未知" {
+		t.Fatalf("空状态应回落到占位文案，实际 %q", got)
+	}
+	if got := stateOr("error"); got != "error" {
+		t.Fatalf("非空状态应原样返回，实际 %q", got)
+	}
+}