router: extract stage-0 grammars into TryFastPath (slice 10)

internal/router/router.go

@@ -72,48 +72,14 @@ func New(cfg Config) *Router {
 //	since(key)==null → don't fire: a misrouted fact is a confident wrong write,
 //	worse than a gap).
 func (r *Router) Route(ctx context.Context, utterance string, now time.Time) (Decision, error) {
-	// stage 0 — exact match / grammar. First match wins; grammars are ordered.
-	// Grammars like time/date/reminder don't expect a wake-word prefix, but
-	// the STT often includes one (transcribed phonetically, any script) — try
-	// the wake-stripped utterance too so those grammars still fire.
-	stripped, hadWake := StripWakeToken(utterance)
-	// declinedBuild — the grammars that matched the shape and refused the
-	// content, kept for the decision record (V-564) so a reader can tell that
-	// rule from one whose pattern never fired.
-	var declinedBuild map[int]bool
-	for i, g := range r.grammars {
-		d, matched, ok := g.Evaluate(utterance)
-		if !matched && hadWake {
-			d, matched, ok = g.Evaluate(stripped)
-		}
-		if !matched {
-			continue
-		}
-		if !ok {
-			if declinedBuild == nil {
-				declinedBuild = map[int]bool{}
-			}
-			declinedBuild[i] = true
-			continue // grammar matched shape but not content → fall through
-		}
-		d.Utterance = utterance
-		d.Producer = RouteProducerGrammar
-		// A literal pattern named that destination, which is the one provenance
-		// allowed to take the personal boundary off a turn (V-666). Set here and
-		// nowhere else, so no other arm of the cascade can claim it.
-		d.SourceAnchored = d.Source != SourceUnknown
-		// The grammar decided the intent; the extractor fills the slots it did
-		// not match (V-572). See fillMatchedSlots for why every grammar gets it.
-		r.fillMatchedSlots(ctx, &d, now)
-		// Capability selection: deterministic grammars that already resolved Fn
-		// (wakeword-act, praxis, task-status) bypass the general selector.
-		// SelectCapability records the existing result with
-		// InputKind=SelectionDeterministic.
-		applyCapabilityToSlots(&d, SelectCapability(d, r.extractor.Acts))
-		r.noteGrammarOutcomes(ctx, i+1, declinedBuild, g.Name, d.Intent)
-		return d, nil
+	// stage 0 — deterministic fast path. First match wins; grammars are ordered.
+	fast, err := r.TryFastPath(ctx, NormalizedInput{Text: utterance}, now)
+	if err != nil {
+		return Decision{}, err
+	}
+	if fast.Matched {
+		return fast.Decision, nil
 	}
-	r.noteGrammarOutcomes(ctx, len(r.grammars), declinedBuild, "", "")
 
 	// stage 0b — routing heads (when wired). A softmax over the label set, so
 	// it cannot name an intent or a destination that does not exist, and its