fix(邮件发送): 适配 MailerSend SMTP 并迁移基础设施至 1Panel

Motivation:
将通知服务部署到 1Panel 生产环境，集成 MailerSend 邮件服务，修复 SMTP 协议中 MAIL FROM 命令因携带显示名而导致的发送失败问题。

Changes:

* 修复 SMTP MAIL FROM 命令传入带显示名的完整地址导致发送失败的问题，新增 extractEmailAddr 提取裸地址
* 更新 SMTP 配置为 MailerSend 真实凭证，From 地址适配其域名验证要求
* 移除 docker-compose 中内置的 MySQL/Redis 服务，改为依赖外部 1Panel 基础设施
* 更新环境变量为生产环境实际凭据

docker-compose.yml

@@ -1,58 +1,17 @@
 version: '3.8'
 
 services:
-  mysql:
-    image: mysql:8.0
-    environment:
-      MYSQL_ROOT_PASSWORD: rootpass
-      MYSQL_DATABASE: notification
-      MYSQL_USER: notify
-      MYSQL_PASSWORD: notify
-    ports:
-      - "3306:3306"
-    volumes:
-      - mysql_data:/var/lib/mysql
-    healthcheck:
-      test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
-      interval: 5s
-      timeout: 3s
-      retries: 10
-    networks:
-      - 1panel-network
-
-  redis:
-    image: redis:7-alpine
-    ports:
-      - "6379:6379"
-    healthcheck:
-      test: ["CMD", "redis-cli", "ping"]
-      interval: 5s
-      timeout: 3s
-      retries: 5
-    networks:
-      - 1panel-network
-
   api:
     build: .
     ports:
       - "8080:8080"
     environment:
-      - DB_PASSWORD=notify
-      - SMTP_PASSWORD=
-      - NOTIFY_DATABASE_HOST=mysql
-      - NOTIFY_REDIS_HOST=redis
-    depends_on:
-      mysql:
-        condition: service_healthy
-      redis:
-        condition: service_healthy
+      - SMTP_PASSWORD=mssp.92QdSYS.3z0vklo982xl7qrx.tSlSpXs
+      - DB_PASSWORD=7Qay8mksnwrCffGi
     restart: unless-stopped
     networks:
       - 1panel-network
 
-volumes:
-  mysql_data:
-
 networks:
   1panel-network:
     external: true