Retry only a failed apply that is not held, answer a repeated compose from the last pass, and say the try the refusal named (issue 774, review round 1)

The verb compose has no warrant (ADR 0563 §2): Agent.Retry released a module held for a failed backup and re-applied
one already running its want. RetryFailed tries again only a failed apply not held, and refuses in words otherwise.
A hand ask no longer restarts the growing bound, and a pass less than askedWithin old is the answer, so a caller in a
loop drives no passes against the vault. A composer whose loop ended refuses at once. The retry line said try N+1.
The test's first shadow now ends before slowAfter is set, a race the race detector found under the new timing.

cmd/mesh-host/engineseat.go

@@ -306,11 +306,18 @@ func composeFrom(current *agentNow, composer *atomic.Pointer[selfcompose.Compose
 			return nil, errors.New("this node composes none of its own modules now (it applies the controller's " +
 				"compositions, or its node agent is starting), so there is no pass to make")
 		}
-		ag := current.get()
+		out := map[string]any{}
 		if module != "" {
-			if ag == nil || !ag.Placed("")[module] {
-				return nil, fmt.Errorf("%s has no want on this machine, so there is no apply of it to try again", module)
+			// Only a failed apply that is not held is tried again; what runs is never taken away (review round 1: the
+			// verb has no warrant, ADR 0563 §2, and a hold for a failed backup is the operator's to release, ADR 0568 §4).
+			ag := current.get()
+			if ag == nil {
+				return nil, errors.New("this engine's node agent has not started, so no apply is tried again")
 			}
+			if err := ag.RetryFailed(module); err != nil {
+				return nil, err
+			}
+			out["retried"] = module
 		}
 		ctx, cancel := context.WithTimeout(context.Background(), composeReadFor)
 		defer cancel()
@@ -318,11 +325,7 @@ func composeFrom(current *agentNow, composer *atomic.Pointer[selfcompose.Compose
 		if err != nil {
 			return nil, err
 		}
-		out := map[string]any{"pass": pass}
-		if module != "" {
-			ag.Retry(module)
-			out["retried"] = module
-		}
+		out["pass"] = pass
 		return out, nil
 	}
 }