fix: deduplicate mirrored Linux RAPL counters

[lntutor]

Description

Drop mirrored nonzero Linux RAPL package counters at monitoring startup while preserving distinct package counters, zero counters, and DRAM domains. The documentation explains the multi-die mirrored-counter behavior.

Related Issue

Fixes #1274

Motivation and Context

Some Linux multi-die systems expose mirrored package-energy counters. Counting each mirror separately overstates CPU energy consumption, while indiscriminate deduplication could incorrectly remove distinct or zero-valued counters.

How Has This Been Tested?

• uv run pytest tests/test_rapl_mmio_scanning.py -q
• uv run pytest tests/test_cpu.py tests/test_rapl_mmio_scanning.py tests/test_rapl_parameters.py -q
• uv run ruff check codecarbon/core/cpu.py tests/test_rapl_mmio_scanning.py
• uv run ruff format --check codecarbon/core/cpu.py tests/test_rapl_mmio_scanning.py
• git diff --check

Screenshots (if appropriate):

Not applicable.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

AI Usage Disclosure

• 🟥 AI-vibecoded: You cannot explain the logic. Car analogy : the car drive by itself, you are outside it and just tell it where to go.
• 🟠 AI-generated: Car analogy : the car drive by itself, you are inside and give instructions.
• ⭐ AI-assisted. Car analogy : you drive the car, AI help you find your way.
• ♻️ No AI used. Car analogy : you drive the car.

OpenAI Codex assisted with implementation, tests, and documentation preparation. I personally reviewed and tested every submitted line, understand the implementation, and can explain and maintain it.

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the docs/how-to/contributing.md document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[SaboniAmine]

Thanks for your contribution, that seems great!
Letting @benoit-cty validate the dedup mechanism, as he worked on the windows side.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.79%. Comparing base (663db8f) to head (3a116e8).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1276      +/-   ##
==========================================
+ Coverage   89.70%   89.79%   +0.09%     
==========================================
  Files          48       48              
  Lines        4778     4791      +13     
==========================================
+ Hits         4286     4302      +16     
+ Misses        492      489       -3     

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[benoit-cty]

Hello, you have created more than 20 repository today, I suspect you are an OpenClaw agent. I'm not against AI contribution, but a human must be accountable and willing to contribute to our project.

Please respect the PR submission template.

We will merge EMI PR in a few days then look back at this PR.

[lntutor]

Updated the PR description to the complete repository template, including the required 🟠 AI-generated disclosure. I personally reviewed and tested every submitted line, understand the implementation, and can explain and support it through review and after merge.