v0.20.0 — named middleware registry

Register middleware by name, reference it anywhere:

router.named({ auth, admin });

router.get("/dashboard", handler).use("auth");
router.group(() => { … }).use(["auth", "admin"]);
router.resource("posts", PostController).use(["store", "update"], "auth");

Names resolve when the app builds (unknown names throw immediately). Raw functions still work everywhere. See docs/middleware.md.