Fix/kubelet idempotency

[Aman-Cool]

Make kubelet redirect/revert idempotent

Summary

Fixes unnecessary kubelet restarts during YurtHub convert/revert by making the operations truly idempotent.
Kubelet is now restarted only when configuration or environment actually changes.

Root Cause

Kubelet config helpers did not indicate whether they modified state, so convert/revert paths always restarted kubelet—even when the node was already correctly configured.

Fix

• Return change status from kubelet config helpers
• Restart kubelet only on real config/env changes
• Add tests to verify no-op vs change behavior

Impact

• Eliminates redundant kubelet restarts
• Safe for reconciliation loops
• Enables reliable label-driven YurtHub automation

Backward Compatibility

No breaking changes. Behavior is unchanged except redundant restarts are avoided.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Aman-Cool]

@vie-serendipity @zyjhtangtang ,Fixes repeated kubelet restarts by making redirect/revert idempotent. Kubelet restarts only on real config or env changes.

[codecov]

Codecov Report

❌ Patch coverage is 17.50000% with 33 lines in your changes missing coverage. Please review.
✅ Project coverage is 44.16%. Comparing base (ed4eb0a) to head (4ecfba0).
⚠️ Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/node-servant/components/kubelet.go	15.38%	33 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2511      +/-   ##
==========================================
+ Coverage   44.09%   44.16%   +0.06%     
==========================================
  Files         399      399              
  Lines       26554    26585      +31     
==========================================
+ Hits        11710    11740      +30     
+ Misses      13782    13780       -2     
- Partials     1062     1065       +3     

Flag	Coverage Δ
unittests	44.16% <17.50%> (+0.06%)	⬆️

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[Aman-Cool]

@zhangzhenyuyu ,quick ping — this PR is ready for review and CI is passing.
Please let me know if you’re the right person to review or if I should loop someone else in. Thanks!