Docker images are not versioned - everything is `latest`

[fantom0005]

Your Docker images have no versioning whatsoever - everything gets tagged as latest. This is causing real problems:

• I rebuild my template and suddenly my app stops working
• No way to know what changed or roll back to a working version
• Can't pin to a stable version for production use
• Every rebuild is a gamble

Impact

This makes it impossible to use your platform reliably in production. When something breaks, there's no way to identify if it's due to your recent changes or debug what went wrong.

I shouldn't have to avoid rebuilding templates because I'm afraid my application will randomly break.

[linear]

ENG-3084