Arm task #68's event-driven route healing over the native registry feed: every settled
burst of Node/Port changes re-runs the mixer's reconcile, so a routed sink whose
node was recreated by a USB re-enumeration gets its name-keyed route links re-issued
the moment its PORTS register (node-exists ≠ ports-exist — the boot-time one-shot's
exact failure), and a scene-restore link that lost that race heals instead of staying
silenced. Returns the started RouteHealer; the caller stops it on shutdown.
Arm task #68's event-driven route healing over the native registry feed: every settled burst of Node/Port changes re-runs the mixer's reconcile, so a routed sink whose node was recreated by a USB re-enumeration gets its name-keyed route links re-issued the moment its PORTS register (node-exists ≠ ports-exist — the boot-time one-shot's exact failure), and a scene-restore link that lost that race heals instead of staying silenced. Returns the started RouteHealer; the caller stops it on shutdown.