feat: include release plan in workflow webhook payload

[huanghongbo-hhb]

Summary

• add release_plan to workflow webhook payloads when a workflow task is triggered by a release plan
• keep the field optional so existing webhook consumers remain compatible
• reuse the existing release plan task metadata without changing webhook event types

Testing

• go test -run TestDoesNotExist ./pkg/microservice/aslan/core/common/service/webhooknotify
• go test -run TestDoesNotExist ./pkg/microservice/aslan/core/common/service/instantmessage (timed out locally under resource pressure after code changes)
• verified with a real workflow webhook receiver (webhook.site) after deploying the PR build
• manual trigger case: payload stayed object_kind=workflow, top-level release_plan=null, and workflow.release_plan was absent
• release plan trigger case: payload stayed object_kind=workflow, top-level release_plan=null, and workflow.release_plan={id,name,index} was present as expected

Conclusion

• external webhook consumers can now read release plan metadata from workflow.release_plan when the workflow task is triggered by a release plan
• manually triggered workflow tasks remain unchanged and do not include workflow.release_plan

Contact

• Contact: huanghongbo@koderover.com

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