The plans verb: what the last merges produced and where each stands (hq ADR 0162)

The mesh's seat answers plans — the recent plans with their tier, what each waits for and since when,
or one plan whole given its id — so the console reads a merge's progress where it reads everything
else, instead of a person reading the daemon's log.

cmd/mesh-controller/seatverbs.go

@@ -69,6 +69,11 @@ func argvFor(verb string, args map[string]any) ([]string, error) {
 			return []string{"builds", m}, nil
 		}
 		return []string{"builds"}, nil
+	case "plans":
+		if id := str("id"); id != "" {
+			return []string{"plans", id}, nil
+		}
+		return []string{"plans"}, nil
 	case "plan":
 		if err := need("node"); err != nil {
 			return nil, err