seat: a push to a named machine waits for the machine's answer, so its call says how it went (issue 629)

The seat ran `push <node> --wait 0`, so a push's call ended at "sent" and nobody learned whether the machine applied it. The caller is answered before a push starts (answersFirst, issue 265), so waiting holds nobody: the call now waits up to two minutes for the machine's own report and keeps it, applied, refused with the machine's reason, or each failed resource with its error.

cmd/mesh-controller/seatverbs_schema_test.go

@@ -146,7 +146,8 @@ func TestAnArgumentAVerbDoesNotDeclareIsRefused(t *testing.T) {
 // naming one beside behind is refused rather than one of the two guessed.
 func TestAPushIsOneMachineOrSaysItIsTheWholeMesh(t *testing.T) {
 	argv, err := argvFor("push", map[string]any{"node": "g1", "why": "w"})
-	if err != nil || strings.Join(argv, " ") != "push g1 --wait 0 --why w" {
+	// A named push waits for the machine's own answer, so the call says how it went (novox/hq issue 629).
+	if err != nil || strings.Join(argv, " ") != "push g1 --wait 2m0s --why w" {
 		t.Fatalf("a named push: %v %v", argv, err)
 	}
 	for _, args := range []map[string]any{{"why": "w"}, {"behind": "true", "why": "w"}} {