Name the account whose own manager runs a unit, so a wait for a new login is not read as a fault (hq ADR 0254, issue 318)

internal/link/messages.go

@@ -350,6 +350,11 @@ type ResourceHealth struct {
 	// provision it exercises, for the controller to hold what it finds under the provider (to-be 48 §6).
 	Check string `json:"check,omitempty"`
 	Needs string `json:"needs,omitempty"`
+	// Account is the account whose own service manager runs it, for a unit or a service in an account's
+	// manager, and the account itself for a resource of kind KindAccount (novox/hq ADR 0254): what lets the
+	// controller tell a unit that cannot run before a new login from one that is broken. Empty for anything
+	// the machine's own manager or a container runtime runs.
+	Account string `json:"account,omitempty"`
 }
 
 // HealthSaid is the health event: a machine's statement between its reports, on HealthSubject.