feat: add effective latency probe tracking

[offmor]

Description

This PR adds probe tracking for effective latency measurement in marilib.

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Testing of Node / Gateway (if applicable)

• I tested this change with _10__ nodes and _1__ gateways.
• I let it run for the following amount of time: _2mins__

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Additional Notes

[geonnave]

Thanks! After adding this, how did you perceive the results changing? e.g. you should see the latency spiking up as you walk away from the gateway (due to reduced PDR), and then latency going down as you get very close to the gateway (near perfect PDR).

[offmor]

Thanks! After adding this, how did you perceive the results changing? e.g. you should see the latency spiking up as you walk away from the gateway (due to reduced PDR), and then latency going down as you get very close to the gateway (near perfect PDR).

Thanks! After adding this, how did you perceive the results changing? e.g. you should see the latency spiking up as you walk away from the gateway (due to reduced PDR), and then latency going down as you get very close to the gateway (near perfect PDR).

Thanks for the question. When one panel (10 nodes) is close to the gateway (PDR near perfect), Effective Avg tracks RTT Avg closely. When I moved the panel farther from the gateway, PDR dropped quickly. RTT Avg stayed around ~230 ms, while Effective latency rose to around ~400ms. In other words, effective latency rises as overall PDR falls.

[geonnave]

Perfect, thanks!

I modified this to target develop branch, and then I am merging it.