Keep what each machine says of what it runs, raise it, and gate on it (hq ADR 0240, to-be 48 Phase A)

The gate judged a module by what the mesh saw from outside, so a container that
crash-looped after it applied passed it. Each machine's node-engine now states
the health of every long-running resource it runs; the controller keeps the
newest statement per machine, raises module.<module>.<machine>.unhealthy on the
second statement in a row, clears it on the first that does not say it, and the
gate passes a module only when every long-running resource of it is stated
healthy since the send. An engine that states nothing is judged as before.

internal/conditions/condition.go

@@ -46,11 +46,14 @@ const (
 	ScopeMesh     = "mesh"
 	// ScopeDelivery is a delivery mesh-delivery owns, by its id (novox/hq ADR 0239).
 	ScopeDelivery = "delivery"
+	// ScopeModule is a module on a machine, by `<module>.<machine>`: what it runs is not healthy there
+	// (novox/hq ADR 0240).
+	ScopeModule = "module"
 )
 
 // Scopes is every scope, in the order a person reads them.
 var Scopes = []string{ScopeMachine, ScopePlan, ScopeCall, ScopeBuild, ScopeMerge, ScopeProvider,
-	ScopeSeat, ScopeBus, ScopeCore, ScopeProbe, ScopeMesh, ScopeDelivery}
+	ScopeSeat, ScopeBus, ScopeCore, ScopeProbe, ScopeMesh, ScopeDelivery, ScopeModule}
 
 // Who resolves a condition.
 const (