stage0: one rest-of-day grammar, not two (V-530)

The textual merge in fe489df left a second rest-of-day-query grammar inside
NarrativeQueryGrammars. buildRouter wires the agenda grammars first, so the
copy never claimed a turn, and narrative_test.go only ever indexed the
narrative rule beside it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

internal/router/narrative_test.go

@@ -15,7 +15,7 @@ func narrativeRouter(t *testing.T) *Router {
 	r.grammars = append(r.grammars, AgendaQueryGrammars()...)
 	r.grammars = append(r.grammars, TaskListGrammar())
 	r.grammars = append(r.grammars, TaskCaptureGrammar())
-	r.grammars = append(r.grammars, NarrativeQueryGrammars()[1])
+	r.grammars = append(r.grammars, NarrativeQueryGrammars()...)
 	return r
 }