Show and change the build queue through the controller, and have plans follow it (hq ADR 0219)

Nothing showed what waited for a build machine, and an ask could not be
dropped without leaving the plan that made it waiting for ever. New verbs:
queue, cancel, clear, rebuild, replay, kill, pause, resume, and plans retry.
Every ask a person drops is recorded failed through the same take-in as a
failed build; a plan keeps the id it asked each module under and matches
its outcome by it. replay is a dry run unless registered, and registering
an older commit than one registered since needs --older (hq issue 207).
A plan waiting on a seat paused on every holder says so and is not late;
a failed plan can be retried, and a rebuild joins the plan holding the
module instead of running beside it.

internal/catalogue/verbs.go

@@ -97,6 +97,7 @@ var ControllerVerbs = []Verb{
 			"id":         "a plan's id (as `plans` lists them): that plan, tier by tier",
 			"stop":       "a plan's id: stop it — what was asked still builds, nothing further is asked",
 			"close":      "a plan's id: close a plan that will not move again, as failed by hand (novox/hq issue 254)",
+			"retry":      "a failed plan's id: ask its failed builds again under new ids, and carry the plan on from that tier (novox/hq ADR 0219)",
 			"repository": "owner/repository: the plan a merge there would produce, saving nothing (what-if); with paths or modules",
 			"paths":      "with repository: the files the merge would change, comma-separated, from the repository's root",
 			"modules":    "with repository: or the modules it would change, comma-separated",
@@ -156,6 +157,36 @@ var ControllerVerbs = []Verb{
 		Input: schema(map[string]string{
 			"command": "the command line, as the controller's binary takes it; quotes group a word with spaces",
 		}, []string{"command"})},
+	// The build queue, controlled by hand (novox/hq ADR 0219). Every verb that drops an ask leaves a
+	// failed outcome for it, so a plan waiting on it fails visibly instead of hanging.
+	{Name: "queue", Description: "Every ask in the build queue: waiting, in flight (on which machine, for how long), " +
+		"and dead (handed out as often as allowed and never settled) — each with its id, repository, path, ref and when it was asked.",
+		Input: schema(nil, nil)},
+	{Name: "cancel", Description: "Drop one waiting or dead ask from the build queue; its outcome is recorded failed, " +
+		"cancelled by hand, and a plan that asked for it fails. One in flight is refused: `kill` ends it where it runs.",
+		Input: schema(map[string]string{"id": "the ask's build id, as `queue` lists it"}, []string{"id"})},
+	{Name: "clear", Description: "Cancel every waiting ask in the build queue — and with dead, every dead one too — each " +
+		"recorded failed, cancelled by hand. Never touches one in flight.",
+		Input: schema(map[string]string{"dead": "\"true\" to cancel the dead asks as well"}, nil)},
+	{Name: "rebuild", Description: "Ask a module's current source again under a new id — the branch it follows — or, given a " +
+		"build's id, that build's repository, path and ref. A module a plan holds unbuilt or failed joins that plan. Answers the new id.",
+		Input: schema(map[string]string{"what": "a module's name, or a build's id"}, []string{"what"})},
+	{Name: "replay", Description: "Ask a recorded build's repository and path again at the commit it built, under a new id. " +
+		"A dry run unless register: nothing recorded or registered. Registering is refused when a newer build of the module " +
+		"is registered — it would roll the older commit out (novox/hq issue 207) — unless older says so.",
+		Input: schema(map[string]string{
+			"id":       "the build's id",
+			"register": "\"true\" to register what it builds",
+			"older":    "\"true\", with register: even though a newer build of the module is registered",
+		}, []string{"id"})},
+	{Name: "kill", Description: "End a build where it runs: the machine that took it stops its commands and containers and " +
+		"announces it failed, killed by hand — settled, never handed to another machine.",
+		Input: schema(map[string]string{"id": "the build's id"}, []string{"id"})},
+	{Name: "pause", Description: "The build seat's holder on one machine — or every holder — takes no new build until resumed; " +
+		"a build running finishes. Kept across a restart of the holder. A plan waiting on a paused seat says so and is not late.",
+		Input: schema(map[string]string{"node": "one machine; every holder when absent"}, nil)},
+	{Name: "resume", Description: "The build seat's holder on one machine — or every holder — takes builds again.",
+		Input: schema(map[string]string{"node": "one machine; every holder when absent"}, nil)},
 	{Name: "build", Description: "Have the build machine build a repository. Answers at once with the build's id: " +
 		"`builds` with that id follows it line by line, and the module is registered when the outcome comes.",
 		Input: schema(map[string]string{