Delete the builder, the build asks, the build queue and the merge gate: the builder's keys are the only way a module is built (issues 1851, 1299, 1318; C2b-C5, C10)

The controller asks no build of anybody (ADR 0501 §5, ADR 0525 clause 6, ADR 0503 §3). Every module of a walk is taken from the
builder's done key; a key not done yet waits, named in the plan, and never fails it.

- C2b/C2c: internal/builder and cmd/mesh-controller's asks go (askABuild, onlyTheBuildersOwn, buildOneAsked, takeIn from an
  outcome, buildAgentsOwn, the builder's say and its fallback, the daemon hearing an outcome). The server follows the retired
  seats' built subjects only to let go of them, because the installer's carried user list names them.
- C2d: replay, queue, cancel, clear, kill, pause, resume, delivery-check, check-here and merge-gate are refused by name.
- C3: the check queues (CHECKS_READY, CHECKS_OTHER) and their workers, the checks-running and plans-building buckets and
  their grants, the build queue and its hold (plans_building.go, queue.go, link/holds.go, builds_nats.go, checks_nats.go).
- C4: merge_gate*.go, the pull request's repo-check path, the Checked event and its layers; a pull request asks the
  controller nothing but to tell mesh-config what its head declares.
- C5: the builds bucket is written only by key_takein.
- C10 (help and refusals): the terminal's help lists only what is served.

Integration tests of the plan's tiers, sends, stops and retries now run on a stand-in builder with a done key for every
module (walk_keys_scaffold_integration_test.go); the tests of the asks, the queue, the merge gate and the replays are deleted.

cmd/mesh-controller/grants_step_test.go

@@ -9,9 +9,7 @@ import (
 	"strings"
 	"testing"
 
-	"git.novox.be/novox/mesh-sdk/go/catalogue"
 	"github.com/novox/mesh-controller/internal/inventory"
-	"github.com/novox/mesh-controller/internal/link"
 )
 
 // The grants reach the bus before the gate (novox/hq issue 490).
@@ -176,35 +174,3 @@ func TestTheGrantsStepKeepsOneMachinesBuilds(t *testing.T) {
 		t.Error("the grants step keeps the builds of a machine it does not send")
 	}
 }
-
-// The delivery plan says the step before the merge.
-func TestAChangePlanSaysTheGrantsStep(t *testing.T) {
-	const catalogue_ = "http://forge.internal:20000/novox/mesh-catalog.git"
-	entry := func(name string, on ...string) inventory.Entry {
-		e := fromRepo(name, catalogue_, "modules/"+name)
-		e.Source.BuiltFrom = "old"
-		e.On = on
-		return e
-	}
-	nats := entry("nats", "novox")
-	nats.Manifest.BusUsers = "/etc/nats/users.conf"
-	nats.Manifest.Claims = []catalogue.Claim{{Name: catalogue.BrokerSeat, Scope: catalogue.ScopeMesh}}
-	restic := entry("restic", "ace", "novox", "shanks")
-	only := entry("bus-tools", "novox")
-	entries := []inventory.Entry{nats, restic, only}
-	rollsOut := func(string) (inventory.Upgrade, bool) { return inventory.Upgrade{RollOut: true}, true }
-	plan := func(paths ...string) link.ChangePlan {
-		m := link.SourceMoved{Owner: "novox", Repo: "mesh-catalog", Base: "main", Commit: "head", Paths: paths}
-		return changePlanOf("novox/mesh-catalog", "main", "head", reachOfMerge(m, entries, nil, nil), entries, rollsOut)
-	}
-
-	text := planText(plan("modules/restic/module.json"))
-	if !strings.Contains(text, "grants step: if this changes what the bus's user list says (a new tool, subject or "+
-		"user), novox is sent that list alone, every build there kept, before restic is judged on its first machine") {
-		t.Errorf("the change plan does not say the grants step:\n%s", text)
-	}
-	// A module only on the bus's machine goes there with the list in its own send: no step of its own.
-	if text := planText(plan("modules/bus-tools/module.json")); strings.Contains(text, "grants step") {
-		t.Errorf("a module on the bus's machine alone reads:\n%s", text)
-	}
-}