Latency/disconnects/availability overlay on the extension icon

[dmishh]

• Setting (UI section) + default value
• Show latency on the badge
• Show disconnects count on the badge
• Show availability today on the badge
• Add to QA checklist

Discussed in #121

^{Originally posted by dmishh September 21, 2024}
Show latency in a text block on top of the extension icon