enhance: balance partition shards by disk usage

[sunby]

related: #50733
depends on: #50835

What

• Add ScoreBasedBalancer shard disk balance path for collections with namespace.mode=partition.
• Use cache shard disk usage stats to move one improving shard per balance round, with in-flight shard move projection and busy-shard skipping.
• Move the QueryCoord shard delegator first; once the delegator is on the target, move movable sealed segments for that shard to the same node.

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[sre-ci-robot]

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[sre-ci-robot]

❌ CI Loop Results e30c1dc

Stage	Result	Duration	Tests
✅ Build	SUCCESS	17.2min	-
✅ Code-Check	SUCCESS	11.1min	-
❌ UT-GO	FAILURE	22.1min	1071 total, 1071 passed, 0 failed
✅ UT-Integration	SUCCESS	25.3min	46 total, 46 passed, 0 failed
❌ UT-CPP-Cov	FAILURE	62.8min	6277 total, failed (process exit non-zero; failed cases unavailable)

Total: 83min | Pipeline | Artifacts
Diff Coverage: CPP 37.1% (43 hit, 73 miss, 116 measurable lines, 161 unmeasured)
Total Patch Coverage: 37.1% (43/116 measurable lines, 161 unmeasured)

Failed Test Logs:

• UT-GO: view log
• UT-CPP-Cov: view log

[codecov]

Codecov Report

❌ Patch coverage is 0% with 49 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.78%. Comparing base (ae1d566) to head (8073f5d).
⚠️ Report is 346 commits behind head on master.

Files with missing lines	Patch %	Lines
internal/core/src/monitor/monitor_c.cpp	0.00%	49 Missing ⚠️

❌ Your patch check has failed because the patch coverage (0.00%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #50890       +/-   ##
===========================================
+ Coverage   79.39%   85.78%    +6.38%     
===========================================
  Files        2290      690     -1600     
  Lines      418096   129540   -288556     
===========================================
- Hits       331961   111121   -220840     
+ Misses      75946    18367    -57579     
+ Partials    10189       52    -10137     

Components	Coverage Δ
Client	∅ <ø> (∅)
Core	86.46% <57.26%> (+<0.01%)	⬆️
Go	∅ <ø> (∅)

Files with missing lines	Coverage Δ
.../src/segcore/storagev1translator/ChunkTranslator.h	100.00% <ø> (ø)
internal/core/src/monitor/monitor_c.cpp	14.03% <0.00%> (-85.97%)	⬇️

... and 1603 files with indirect coverage changes

🚀 New features to boost your workflow:

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[sunby]

/ci-rerun-build-ut-cov

[sre-ci-robot]

✅ CI Loop Results af5dc7c

Stage	Result	Duration	Tests
✅ Build	SUCCESS	16.7min	-
✅ Code-Check	SUCCESS	10.9min	-
✅ UT-GO	SUCCESS	21.9min	1071 total, 1071 passed, 0 failed
✅ UT-Integration	SUCCESS	25.2min	46 total, 46 passed, 0 failed
✅ UT-CPP-Cov	SUCCESS	63.7min	8029 total, 8029 passed, 0 failed

Total: 87min | Pipeline | Artifacts

Overall Coverage: 72.1%
Diff Coverage: CPP 37.1% (43 hit, 73 miss, 116 measurable lines, 161 unmeasured) | Go 84.3% (327 hit, 61 miss, 388 measurable lines, 2346 unmeasured)
Diff Coverage HTML: view changed lines
Go Patch Warning: WARNING: Go patch coverage is partial; 2346 changed lines were unmeasured.
Total Patch Coverage: 73.4% (370/504 measurable lines, 2507 unmeasured)

[sre-ci-robot]

✅ CI Loop Results 076558b

Stage	Result	Duration	Tests
✅ Build	SUCCESS	14.0min	-
✅ Code-Check	SUCCESS	6.8min	-
✅ UT-Integration	SUCCESS	25.1min	46 total, 46 passed, 0 failed
✅ UT-GO	SUCCESS	21.2min	1071 total, 1071 passed, 0 failed
✅ UT-CPP-Cov	SUCCESS	58.3min	8047 total, 8047 passed, 0 failed

Total: 125min | Pipeline | Artifacts

Overall Coverage: 72.2%
Diff Coverage: CPP 0.0% (0 hit, 51 miss, 51 measurable lines, 57 unmeasured) | Go 84.2% (314 hit, 59 miss, 373 measurable lines, 2342 unmeasured)
Diff Coverage HTML: view changed lines
Go Patch Warning: WARNING: Go patch coverage is partial; 2342 changed lines were unmeasured.
Total Patch Coverage: 74.1% (314/424 measurable lines, 2399 unmeasured)

[sunby]

/ci-rerun-gosdk
/ci-rerun-e2e-default

[sunby]

/ci-rerun-gosdk

[sunby]

/ci-rerun-e2e-default

[sre-ci-robot]

❌ CI Loop Results 6b3c8d9

Stage	Result	Duration	Tests
✅ Build	SUCCESS	14.9min	-
❌ Code-Check	FAILURE	2.0min	-
❌ UT-Integration	SKIPPED	-	-
❌ UT-GO	SKIPPED	-	-
✅ UT-CPP-Cov	SUCCESS	58.3min	8049 total, 8049 passed, 0 failed

Total: 76min | Pipeline | Artifacts
Diff Coverage: CPP 0.0% (0 hit, 51 miss, 51 measurable lines, 58 unmeasured)
Total Patch Coverage: 0.0% (0/51 measurable lines, 58 unmeasured)

Failed Test Logs:

• Code-Check: view log

[sre-ci-robot]

❌ CI Loop Results 648edc8

Stage	Result	Duration	Tests
✅ Build	SUCCESS	14.7min	-
❌ Code-Check	FAILURE	6.2min	-
❌ UT-Integration	SKIPPED	-	-
❌ UT-GO	SKIPPED	-	-
✅ UT-CPP-Cov	SUCCESS	58.5min	8049 total, 8049 passed, 0 failed

Total: 76min | Pipeline | Artifacts
Diff Coverage: CPP 0.0% (0 hit, 51 miss, 51 measurable lines, 57 unmeasured)
Total Patch Coverage: 0.0% (0/51 measurable lines, 57 unmeasured)

Failed Test Logs:

• Code-Check: view log

[sre-ci-robot]

✅ CI Loop Results 54c24f1

Stage	Result	Duration	Tests
✅ Build	SUCCESS	14.7min	-
✅ Code-Check	SUCCESS	7.1min	-
✅ UT-Integration	SUCCESS	25.4min	46 total, 46 passed, 0 failed
✅ UT-GO	SUCCESS	21.4min	1081 total, 1081 passed, 0 failed
✅ UT-CPP-Cov	SUCCESS	60.7min	8049 total, 8049 passed, 0 failed

Total: 83min | Pipeline | Artifacts

Overall Coverage: 72.2%
Diff Coverage: CPP 0.0% (0 hit, 51 miss, 51 measurable lines, 57 unmeasured) | Go 84.2% (314 hit, 59 miss, 373 measurable lines, 2342 unmeasured)
Diff Coverage HTML: view changed lines
Go Patch Warning: WARNING: Go patch coverage is partial; 2342 changed lines were unmeasured.
Total Patch Coverage: 74.1% (314/424 measurable lines, 2399 unmeasured)

[sre-ci-robot]

✅ CI Loop Results 8073f5d

Stage	Result	Duration	Tests
✅ Build	SUCCESS	11.3min	-
✅ Code-Check	SUCCESS	8.7min	-
✅ UT-Integration	SUCCESS	25.2min	46 total, 46 passed, 0 failed
✅ UT-GO	SUCCESS	21.5min	1087 total, 1087 passed, 0 failed
✅ UT-CPP-Cov	SUCCESS	47.1min	8053 total, 8053 passed, 0 failed

Total: 78min | Pipeline | Artifacts

Overall Coverage: 72.3%
Diff Coverage: CPP 0.0% (0 hit, 51 miss, 51 measurable lines, 57 unmeasured) | Go 84.2% (314 hit, 59 miss, 373 measurable lines, 2342 unmeasured)
Diff Coverage HTML: view changed lines
Go Patch Warning: WARNING: Go patch coverage is partial; 2342 changed lines were unmeasured.
Total Patch Coverage: 74.1% (314/424 measurable lines, 2399 unmeasured)

[sunby]

/ci-rerun-ut-go

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
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[sre-ci-robot]

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• PR: enhance: balance partition shards by disk usage #50890
• Title: enhance: balance partition shards by disk usage
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