koordlet: add cpuset sharepool cpu info to metrics.

[tan90github]

Ⅰ. Describe what this PR does

This PR adds the koordlet_cpuset_share_pool_info metric, which exports the specific CPU IDs currently assigned to the Share Pool. The same applies to the BE Share Pool.

For CPU pinning scenarios (e.g., LSE/LSR pods), we should monitor the Share Pool's usage. If too many exclusive cpus are allocated, non-pinned pods may be crowded into a small Share Pool, causing severe CPU contention and node hotspots.

With the koordlet_cpuset_share_pool_info metric, we can easily monitor the CPU utilization of the sharepool through the following PromQL metric, and prevent hot spot issues in advance.

avg(
  irate(node_cpu_seconds_total{instance=~"kind-worker1", mode=~"user"}[5m])
  and on(node, cpu)
  koordlet_cpuset_share_pool_info
)

Ⅱ. Does this pull request fix one issue?

no

Ⅲ. Describe how to verify it

Go to prometheus, and query follow promql

• koordlet_cpuset_share_pool_info{}
• koordlet_cpuset_be_share_pool_info{}

Ⅳ. Special notes for reviews

V. Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests
• All checks passed in make test

[codecov]

Codecov Report

❌ Patch coverage is 5.26316% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.90%. Comparing base (5d018da) to head (cb619c6).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/koordlet/metrics/cpu_cpuset.go	0.00%	12 Missing ⚠️
pkg/koordlet/runtimehooks/hooks/cpuset/rule.go	14.28%	5 Missing and 1 partial ⚠️

❌ Your patch check has failed because the patch coverage (5.26%) is below the target coverage (70.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2800      +/-   ##
==========================================
+ Coverage   67.89%   67.90%   +0.01%     
==========================================
  Files         513      513              
  Lines       52180    52302     +122     
==========================================
+ Hits        35425    35516      +91     
- Misses      13712    13740      +28     
- Partials     3043     3046       +3     

Flag	Coverage Δ
unittests	67.90% <5.26%> (+0.01%)	⬆️

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[tan90github]

/assign @saintube

[koordinator-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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Details

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• pkg/features/OWNERS
• pkg/koordlet/OWNERS

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