[*] Isolated Prom Registry

[abhijeetsharma200]

Description

Part 1 of #1267.

AI & Automation Policy

• I am the human author and take full personal responsibility for every change in this PR.
• No AI or automated generative tool was used in any part of this PR OR I have disclosed all tool(s) below.

AI/automation tools used (leave blank if none):

Tests drafted with the assistance of Gemini 3

Checklist

• Code compiles and existing tests pass locally.
• New or updated tests are included where applicable.
• Documentation is updated where applicable.

[pashagolub]

what is registry and why do we need it?

[abhijeetsharma200]

what is registry and why do we need it?

A registry tracks all registered collectors. When /metrics is scraped, it calls Collect() on each. It enforces consistency at registration time, catching metric conflicts early. Added go and process collectors as they come in the global registry(Docs).

[pashagolub]

Thanks. There is no need in registry