feat(push): implement system notification and push framework

internal/apps/admin/push/custom_events/admin_login.go

@@ -0,0 +1,43 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package custom_events defines custom push notification events.
+package custom_events
+
+import (
+	"context"
+	"time"
+
+	"github.com/Rain-kl/Wavelet/internal/apps/admin/push"
+	"github.com/Rain-kl/Wavelet/internal/model"
+)
+
+// AdminLogin is the metadata definition for the admin login event.
+var AdminLogin = push.EventMetadata{
+	Key:  "admin_login",
+	Name: "管理员登录",
+	DefaultTemplate: push.NotificationMessage{
+		Title:   "管理员登录提醒",
+		Content: "管理员 {{user.username}} 于 {{time}} 从 IP {{ip}} 登录系统。",
+		Level:   "INFO",
+	},
+	Description: "当管理员成功登录系统时触发此通知",
+}
+
+func init() {
+	push.RegisterBuiltInEvent(AdminLogin)
+}
+
+// TriggerAdminLoginEvent triggers the admin login event asynchronously.
+func TriggerAdminLoginEvent(ctx context.Context, user *model.User, ip string) {
+	if user == nil || !user.IsAdmin {
+		return
+	}
+
+	body := map[string]any{
+		"user": user,
+		"ip":   ip,
+		"time": time.Now().Format("2006-01-02 15:04:05"),
+	}
+	push.DefaultTrigger.Trigger(ctx, AdminLogin, body)
+}