feat(notify): upgrade dingtalk alert notifications to actioncard and markdown with rich chinese formatting

[Zara1024]

Summary

关联 Issue

Closes #442

变更背景 (Problem)

目前系统向钉钉机器人（DingTalk Custom Bot）发送告警时，使用的是无样式的纯英文普通文本（msgtype: text），缺乏视觉层级与汉化展示，且容器缺少 8 小时时区偏差。

主要改动 (Solution)

1. 升级为钉钉 ActionCard（独立跳转）/ Markdown 交互式卡片
2. 告警级别与状态多色联动
3. 自动校准 CST 北京时间（消除 8 小时偏差）
4. 交互按钮与操作渲染
5. 单元测试与实机验证

效果截图

Author confirmation

• I have tested locally and all tests pass.

[Zara1024]

Update

Follow-up on #442 / this PR tip 15c05ab — applied the same required correctness fixes as Feishu (#441 review):

• Status: recovery styling depends only on structured Labels["status"]=="resolved" (no subject substring matching such as unresolved / systemd-resolved).
• Active state: localize production status open (and legacy firing) as OPEN (发生中).
• console_url: wire cfg.PublicURL into pipeline + retry so ActionCard buttons render in production.
• Deep link: alert button goes to /alerts/incidents/{id}; visible incident ID on the card.

Test plan

• go test ./internal/pkg/notify/... ./internal/manager/biz/alert -count=1
• Live DingTalk ActionCard webhook send (errcode=0) with OPEN status + incident deep link
• Channel test to 「钉钉机器人」 → accepted: true

@singchia PTAL — DingTalk card feature + the state/console_url fixes above are on this branch.

[Zara1024]

Screenshot (follow-up)

修正后钉钉 ActionCard：status=open（subject 含 unresolved / systemd-resolved 不误判恢复）、可见事件 ID、按钮深链 /devices/{id} + /alerts/incidents/{id}。