router: Router.Route consumes NormalizedInput directly (slice 11)

Change Route from (ctx, utterance string, now) to (ctx, input NormalizedInput, now).
The ingress-constructed NormalizedInput now reaches the cascade intact — no
reconstruction downstream. TryFastPath receives the same input, not a rebuilt one.
All callers (production, eval framework, tests) updated to construct NormalizedInput.

internal/router/eval/reach.go

@@ -214,7 +214,7 @@ func ScoreReach(ctx context.Context, name string, r Router, m router.ActMatcher,
 
 	for _, c := range f.Cases {
 		start := time.Now()
-		d, err := r.Route(ctx, c.Utterance, now)
+		d, err := r.Route(ctx, router.NormalizedInput{Text: c.Utterance}, now)
 		o := ReachOutcome{Case: c, Decision: d, Err: err, Latency: time.Since(start)}
 		lat = append(lat, o.Latency)