fix: deduplicate mirrored Linux RAPL counters

[lntutor]

Summary

• drop mirrored nonzero Linux RAPL package counters at monitoring startup
• preserve distinct package counters, zero counters, and DRAM domains
• document the multi-die mirrored-counter behavior

Fixes #1274

Validation

• 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

[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.