Add configurable cooldown between mined images

[edblu1]

AB#2311

What

Adds a configurable cooldown_seconds interval to the detection selector.

After a frame passes the existing mining filters, it is forwarded only if the
configured interval has elapsed since the last forwarded frame.

Configuration

The cooldown has to be added to the AI Control settings in the SAE Helm
deployment:

aiControl:
  settingsYaml:
    cooldown_seconds: 5

I recommend starting with 5 seconds. Without this configuration, the
cooldown defaults to 0 and is disabled.

Why

AI Cockpit mining can produce bursts of nearly identical frames. These frames
are unwanted during review, especially when images are sent directly from
Cockpit to CVAT, and are generally not needed for training.

This is a first, simple change to reduce near-duplicate images while keeping
the implementation and runtime state minimal.