Answer what the records keep, collect on a person's word, and name a machine's images (hq ADR 0251)

The store's tools and a machine's image pruning decide from the records, so
the controller says them: artifacts (every recorded artifact, kept and why,
eligible, collected on request), collect (the after-build sweep on demand,
a dry run unless confirmed with a why, recorded as a hand act) and images
(what a machine's declaration names, now and as last sent). The sweep is one
implementation with two sets of bounds.

cmd/mesh-controller/seatverbs.go

@@ -573,6 +573,38 @@ func (a *verbArguments) commandLine() ([]string, error) {
 			return argv, nil
 		}
 		return []string{"cleanup", "list", "--json"}, nil
+	// novox/hq ADR 0251.
+	case "artifacts":
+		argv := []string{"artifacts", "--json"}
+		if r := str("repository"); r != "" {
+			argv = append(argv, "--repository", r)
+		}
+		if on("collected") {
+			argv = append(argv, "--collected")
+		}
+		return argv, nil
+	case "collect":
+		argv := []string{"collect", "--json"}
+		if m := str("most"); m != "" {
+			argv = append(argv, "--most", m)
+		}
+		why := str("why")
+		if !on("confirm") {
+			if why != "" {
+				return nil, errors.New("collect takes why only with confirm: without confirm it is a dry run, " +
+					"and a reason for nothing would be recorded nowhere. Nothing was done")
+			}
+			return argv, nil
+		}
+		if err := need("why"); err != nil {
+			return nil, fmt.Errorf("%w: letting go of artifacts is a hand act, which says why. Nothing was done", err)
+		}
+		return append(argv, "--confirm", "--why", why), nil
+	case "images":
+		if err := need("node"); err != nil {
+			return nil, err
+		}
+		return []string{"images", str("node"), "--json"}, nil
 	case "data":
 		argv := []string{"data", "--json"}
 		if m := str("machine"); m != "" {
@@ -768,6 +800,8 @@ func (a *verbArguments) commandLine() ([]string, error) {
 // jsonVerbs are the verbs whose command speaks JSON, so the answer carries it as data as well.
 var jsonVerbs = map[string]bool{"status": true, "seats": true, "plan": true, "collection": true,
 	"hand-acts": true, "durations": true, "conditions": true, "doctor": true, "retire": true, "cleanup": true, "data": true,
+	// What the records say the registries may keep (novox/hq ADR 0251).
+	"artifacts": true, "collect": true, "images": true,
 	// The delivery's owner's verbs answer JSON where they read (plan, order, check, walks) — novox/hq ADR 0239.
 	"delivery": true}
 
@@ -791,6 +825,8 @@ func repairingCommand(argv []string) string {
 		return "retire " + argv[1]
 	case argv[0] == "cleanup" && len(argv) > 1 && argv[1] == "delete":
 		return "cleanup delete"
+	case argv[0] == "collect" && slices.Contains(argv, "--confirm"):
+		return "collect"
 	}
 	return ""
 }