The companion-unit repair stage ran at the END of each boot-reconciler tick, after
reconcile_existing(). On a heavily loaded node that per-app pass takes >60-90s, so a
deleted/lost companion unit (electrs-ui, bitcoin-ui, …) wasn't repaired within any
reasonable window (gate test 31 'deleted unit recreated within one reconcile tick'
timed out at 90s on the 45-app .228 node). Detecting + rewriting a companion unit is
cheap, so spawn it as its own ~interval(30s) loop, independent of the slow app pass.
Handle is aborted when the main loop exits (shutdown uses notify_one, so a second
waiter would steal the wake permit). tick() is now app-reconcile only.
All 4 boot_reconciler cadence tests still green (companion_stage=false in tests).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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