fix(graceful): prevent WaitGroup panic on Ctrl+C shutdown#35578

Draft

ita004 wants to merge 2 commits intogo-gitea:mainfrom

ita004:fix/waitgroup-shutdown-35559

Commits on Oct 3, 2025

fix(graceful): guard WaitGroup.Wait with sync.Once to avoid panic on repeated shutdowns Fixes #35559
ita004
committed

Commits on Oct 5, 2025

fix(graceful): use SafeWaitGroup to prevent WaitGroup reuse panic and reject new work during shutdown
ita004
committed