Update CI to support manual monthly stable Docker releases

[sarayangrh]

Previously, images were only pushed to Docker Hub when changes were merged to main.

This update allows us to manually release a stable version every month from a chosen branch. These releases will use a date tag (e.g., 2026-01-arm64).

[Rain1618]

A few general comments: It might be a good idea to check if there is an existing tag before running workflow_dispatch, rn I think that it will just overwrite it on Docker Hub without warning... Also for like general knowledge purposes, to avoid repeated code you can use this. Looks good tho, I'm gonna approve and up to you if you wanna implement changes!!

[sarayangrh]

A few general comments: It might be a good idea to check if there is an existing tag before running workflow_dispatch, rn I think that it will just overwrite it on Docker Hub without warning... Also for like general knowledge purposes, to avoid repeated code you can use this. Looks good tho, I'm gonna approve and up to you if you wanna implement changes!!

Than you! I'm gonna make some changes according to this. Btw for an existing tag, we want it to just fail or to warn but proceed overwriting?

[Alb33rt]

Could we potentially have a cron job that does this manually automatically? Or would you rather manually push it up every month.

[Alb33rt]

LMK if you prefer to do this manually or with a cron job.