feat(push): add JPush integration for offline message push

Add JPush (极光推送) integration to enable push notifications for offline users. This includes:
- New jpush client package with API for batch push notifications
- Configuration for jpush (enabled, app_key, master_secret, production mode)
- Updated push service to send messages via JPush when users are offline
- Added PushChatMessage method with do-not-disturb checking
- Integrated push service with chat service to notify offline users of new messages
- Updated deployment workflow with JPush and related environment variables

internal/model/push_record.go

@@ -16,6 +16,7 @@ const (
 	PushChannelFCM       PushChannel = "fcm"       // Firebase Cloud Messaging
 	PushChannelAPNs      PushChannel = "apns"      // Apple Push Notification service
 	PushChannelHuawei    PushChannel = "huawei"    // 华为推送
+	PushChannelJPush     PushChannel = "jpush"     // 极光推送
 )
 
 // PushStatus 推送状态