Ask an acknowledgement apart from an approval, change every kept ask by compare-and-set, and rehearse rather than drill (hq ADR 0259, review M1/L2/L3/L7)

- M1: a condition offering both kinds of answer is asked twice: its authorising answers about the
  condition, its acknowledging ones (Silence) apart, so an answer from a channel that only acknowledges
  never ends an approval.
- L2: the asked store creates once and changes only over the revision it read, deciding again on what it
  reads; a stale cancel no longer writes over an act.
- L3: every ask is kept before it is published, one whose publishing failed is marked unsent and asked
  again, and a cancel is kept before it is said. The terminal's test question is now `rehearse`, so it is
  not called what the glossary calls a drill; its two answers are both approve-level.
- L7: two deliveries of one warrant to two controllers at once act exactly once, on a real bus.
- Re-vendored onto mesh-sdk 76902998 (canonical digests): an option binds an asks.Act with each argument
  as arg.<name>.
- The lab's bus fixture composes verified-sender only where the lab says its machine is root-free
  (MESH_LAB_ASKS_ROOT_FREE=true).

cmd/mesh-controller/rehearse_test.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+
+	"git.novox.be/novox/mesh-sdk/go/asks"
+)
+
+// A rehearsal (the live acceptance of novox/hq ADR 0259): its approval is a warrant like any other — claimed once,
+// its act checked against what the option bound, recorded as the operator's decision with who, how and the
+// proofs — and it performs nothing. The reconciling of conditions leaves it open.
+func TestARehearsalsApprovalIsRecordedAndPerformsNothing(t *testing.T) {
+	r := newAskerRig(t)
+	q, options := rehearsalAsk("crehearsal", r.now, askerRehearsalFor)
+	if err := q.Check(r.now); err != nil {
+		t.Fatalf("the rehearsal's ask is refused: %v", err)
+	}
+	r.store["crehearsal"] = asked{ID: "crehearsal", Condition: q.About, Ask: q, Actions: rehearsalActions(), Options: options,
+		State: askOpen, Opened: r.now, Rehearsal: true}
+	if err := r.a.reconcile(context.Background()); err != nil {
+		t.Fatal(err)
+	}
+	if got := r.store["crehearsal"]; got.State != askOpen {
+		t.Fatalf("the reconciling of conditions ended the rehearsal: %+v", got)
+	}
+	approve, _ := q.Option("approve")
+	w := asks.Warrant{Ask: "crehearsal", Asker: "mesh-controller", Outcome: asks.OutcomeChosen, Option: approve.ID,
+		Label: approve.Label, Level: approve.Level, Channel: "telegram", Proofs: []string{"P1"}, At: r.now,
+		AskDigest: q.Digest(), By: &asks.Person{Who: asks.Operator, Kind: "telegram", Identity: "42", Verified: "user id verified"}}
+	answerWith(t, r, w)
+	answerWith(t, r, w) // heard again
+	if len(r.called)+len(r.silenced) != 0 {
+		t.Errorf("a rehearsal performed something: %v %v", r.called, r.silenced)
+	}
+	if len(r.acts) != 1 {
+		t.Fatalf("hand-acts %+v", r.acts)
+	}
+	act := r.acts[0]
+	if act.Verb != handActWarrant || act.By != "the operator, as telegram identity 42" || act.Ask != "crehearsal" ||
+		strings.Join(act.Args, " ") != "rehearsal rehearsal=approve" || act.Outcome != "done" || strings.Join(act.Proofs, ",") != "P1" {
+		t.Errorf("the rehearsal's record: %+v", act)
+	}
+	if !personsDecision(act) {
+		t.Error("a rehearsal's answer counts as a repair")
+	}
+}
+
+// Only the terminal starts a rehearsal: a verb's process is refused before anything is asked.
+func TestARehearsalIsTheTerminalsAlone(t *testing.T) {
+	t.Setenv(verbVar, "mesh-controller.command")
+	if err := rehearseCommand(context.Background(), nil); err == nil || !strings.Contains(err.Error(), "terminal") {
+		t.Fatalf("a verb started a rehearsal: %v", err)
+	}
+}
+
+// askerRehearsalFor is how long the test's rehearsal waits.
+const askerRehearsalFor = 15 * time.Minute