Raise a module's unhealthy urgent when its manifest says why (hq ADR 0355, issue 691)

A broken service people rely on, such as mail, was said only as a warning on
the desktop. A module may now declare unhealthy urgent with what people lose;
the module check refuses it without why or with another severity.

cmd/mesh-controller/module_health.go

@@ -240,6 +240,7 @@ func judgeModuleHealth(ctx context.Context, inv *inventory.Inventory, k *conditi
 			continue
 		}
 		o := moduleUnhealthyObservation(m, node, unhealthy[m])
+		declaredSeverity(&o, hold, m)
 		if hold != nil {
 			if by, held := hold.heldWith(node, m, unhealthy[m]); held {
 				// Held under the provider's condition: nothing of its own, and the provider's says it waits. The
@@ -347,6 +348,7 @@ func sayWaiters(ctx context.Context, k *conditions.Keeper, hold *holding, p cata
 	} else {
 		_, rest := besideAWait(p.Module, rs)
 		o = moduleUnhealthyObservation(p.Module, p.Node, rest)
+		declaredSeverity(&o, hold, p.Module)
 		if said, waits := personWait(p.Module, p.Node, rest); waits {
 			o = reloginObservation(p.Module, p.Node, said, operatorOn(ctx, hold.inv, p.Node), rest)
 		}
@@ -481,6 +483,19 @@ func sayWaitingOn(o *conditions.Observation, waiters []string) {
 	o.Explanation += fmt.Sprintf(" %d module(s) that depend on it wait for it.", len(waiters))
 }
 
+// declaredSeverity raises a module's unhealthy condition urgent when its manifest declares `unhealthy` urgent
+// (novox/hq ADR 0355 §1). Only that condition changes (ADR 0355 §4): a wait for a new login, a module that needs
+// the operator and a directory used as found keep their severities, and without the field, or without a manifest
+// to read it from, it stays the warning it was.
+func declaredSeverity(o *conditions.Observation, hold *holding, module string) {
+	if o.Kind != kindModuleUnhealthy || hold == nil {
+		return
+	}
+	if m, ok := hold.manifestOf(module); ok && m.UnhealthyIsUrgent() {
+		o.Severity = conditions.Urgent
+	}
+}
+
 // moduleUnhealthyObservation is a module unhealthy on a machine, in words: the summary names the module,
 // the machine and what is wrong with each resource; the detail — targets, streaks, since — is evidence.
 func moduleUnhealthyObservation(module, node string, rs []inventory.ResourceHealth) conditions.Observation {