fix: no downtime for multiple workers while restarting

[MostafaFouad0]

Summary

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.

[codspeed-hq]

Merging this PR will not alter performance

✅ 24 untouched benchmarks

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_{Comparing MostafaFouad0:fix/no_downtime_while_restaring (b3d6559) with main (3314dfc)}

[MostafaFouad0]

Related to #2757 , this covers the multi-worker restart-ordering half of that issue, the single-worker case is a separate follow-up.

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}