Draft: POC stage subscription
What does this MR do and why?
POC of stage subscriptions working with the efforts in #223264
This MR is for testing locally purposes with the full stack. Code will be split in dedicated MRs.
References
Screenshots or screen recordings
How to set up and validate locally
MR acceptance checklist
Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.
Related to #580125