Return a grant not written and retry the take-in under a condition; drop the plans' events; grant bucket-deleted, restic's backup word and the operator's hand path (issue 1945; the review's D1, F1, H1 and its notes)

With no send left nothing else writes a missed grant, so the take-in of a done key returns it and tries again every
half minute under an urgent condition until it is written. plan-moved and sent go with the plans. The controller's
first-start deletions are said on a granted subject, a node hears only its backup holder, and the operator's account
writes the hand path, an object replaced included (ADR 0539 clauses 2, 7, 10 and 13).

cmd/mesh-controller/composed_keys_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"errors"
 	"encoding/json"
 	"strings"
 	"testing"
@@ -114,3 +115,15 @@ func TestAChangedUserListIsANewRevisionOfTheBusModulesCompositionAlone(t *testin
 		}
 	}
 }
+
+// 1945 (the review's D1): a grant that is not written is the take-in's error, never swallowed: with no send left,
+// nothing else would write it, and no want could name the fingerprint.
+func TestAGrantNotWrittenIsTheTakeInsError(t *testing.T) {
+	fp := sdkdelivery.SourcePrefix2 + strings.Repeat("c", 64)
+	var acts []string
+	s := stepsFor(&acts, "old", "new", fp, []string{"ace"}, "novox")
+	s.grants = func(context.Context) error { return errors.New("the bucket mesh-controller_grants: not found") }
+	if _, err := s.take(context.Background(), "mesh-mail"); err == nil || !strings.Contains(err.Error(), "grants") {
+		t.Errorf("a grant not written: %v", err)
+	}
+}