Give the stage 0 grammar set one home (V-693)

buildRouter held the real set and baselineGrammars in eval_test.go restated it
by hand, in the daemon's order, with its own comment saying so. Three test files
score against the fixture and nothing compared the two lists. They had already
drifted: BareCaptureGrammar went into the daemon with V-557 and never into the
fixture, so every routing measurement since has scored a set nobody runs. That
is the failure CLAUDE.md warns about by name, and a diff test would have caught
it one grammar late.

The list moves to router.StageZeroGrammars in internal/router/stagezero.go, with
the ordering comments, which are the load-bearing part. buildRouter and the
fixture both call it. One list cannot drift from itself.

Measured before and after on the 96-case fixture: classifier+onnx 72/96, 75.0%
intent, 33.3% destination, identical either way, and the deterministic claim and
reach hash ratchets do not move. So the missing grammar cost no measurable
accuracy. That is the point rather than a reprieve: the fixture had been scoring
the wrong set for four days and nothing could say so.

The invariants caveat is deleted, both entries, since V-692 landed the other
guard in the previous commit. The reasoning for both now sits in docs/routing.md
beside the subsystem, which is where a fix's durable record belongs.

Unrelated and pre-existing: TestONNXPersonalBoundary fails on "я рассказывал
тебе про байкал?" (personal 0.9068, world 0.9413) at the merge base too.

cmd/mavend/voicewire.go

@@ -469,45 +469,9 @@ func buildRouter(emb router.Embedder, acts router.ActMatcher, threshold float64,
 	llmR *router.LLMRouter, heads *router.RouterHeads) *router.Router {
 	cls := router.NewClassifier(emb)
 	seedClassifier(cls)
-	grammars := router.DefaultGrammars(acts)
-	grammars = append(grammars, router.SystemTimeDateGrammars()...)
-	// After the time/date rules on purpose: "какой сегодня день" is a clock
-	// question and must keep reaching replySystem, while "что у меня сегодня"
-	// is an agenda question and must not.
-	grammars = append(grammars, router.AgendaQueryGrammars()...)
-	// Same reason as the agenda rules, for the feeds: "что нового в лентах?"
-	// routed system and answered "пока не умею" (Vikunja #474).
-	// After the agenda rules, which are the narrower claim, and BEFORE the feed
-	// and list rules, which are not: "что такое лента" is a definition question
-	// and the feed rule would take it on the noun alone (V-655).
-	grammars = append(grammars, router.WorldQueryGrammars()...)
-	grammars = append(grammars, router.FeedQueryGrammar())
-	// The list side of the same exposure: a phrasing with no possessive in it
-	// ("список дел") routed system and never reached queryTasks (Vikunja #467).
-	grammars = append(grammars, router.TaskListGrammar())
-	grammars = append(grammars, router.ListGrammars()...)
-	grammars = append(grammars, router.ReminderGrammar())
-	// Before the capture marker, because "отметь" is a capture verb and "отметь
-	// второй пункт" is not a note. The Praxis rules are the narrower claim — a
-	// lifecycle verb AND an item named — so they get first refusal (Vikunja #516).
-	grammars = append(grammars, router.PraxisGrammars()...)
-	// Last, and it matches any utterance shape — its Build is the filter. An
-	// explicit capture marker beats the model, which called it an act and
-	// rewrote the task text (Vikunja #467). After the rules above because a
-	// marker never collides with a clock or agenda question.
-	// After Praxis, whose bare "закрой" claim this rule cannot reach (it needs the
-	// board noun), and before the capture marker, which would otherwise read
-	// "убери из задач купить молоко" as a new task (Vikunja #512).
-	grammars = append(grammars, router.TaskStatusGrammar())
-	// Before the capture markers, which all need an object. A capture verb
-	// alone is a fact with no key, and the clarify path asks for it rather than
-	// letting the model invent an answer (Vikunja #557).
-	grammars = append(grammars, router.BareCaptureGrammar()...)
-	grammars = append(grammars, router.TaskCaptureGrammar())
-	// After the capture marker, so "запиши" still wins over "расскажи", and
-	// last overall because it matches on the first word alone: "расскажи про
-	// X" is a world question the model called a fact (Vikunja #498).
-	grammars = append(grammars, router.NarrativeQueryGrammars()...)
+	// The stage 0 set, in the router package, so the eval fixture runs the rules
+	// the daemon runs (V-693). Order and reasoning live with the list.
+	grammars := router.StageZeroGrammars(acts)
 	return router.New(router.Config{
 		Grammars:   grammars,
 		Classifier: cls,