Add per-container auto-scale-down-after label

Hey!

First of all thank you for your outstanding work.

Would it be possible to implement per container scaling down as well? Just like how the other labels are scanned as well.

Best,
Boti

No file or test is named. Start by locating the existing label-scanning logic and the current scale-down handling, then determine how container-specific values are represented. Done means the auto-scale-down-after label can be applied independently to each container and the existing test coverage verifies that behavior.

Written by the indexing model from the issue text.