perf: migrate pages to Cache Components via root layout opt-out

Remove the per-route 'export const instant = false' opt-outs now that the root layout carries the single Cache Components opt-out. Child pages inherit the opt-out, so admin/mod/radio leaf pages that only access cached or DB data stay instant while runtime-dependent pages remain dynamic. Update the staff-smoke contract test to assert the root-layout contract.

src/app/(site)/settings/2fa/page.tsx

@@ -15,10 +15,6 @@ import { totpKeyUri } from "@/lib/auth/totp";
 import { db, User } from "@/lib/db";
 import { resolveHotelName } from "@/lib/hotel-name";
 
-// TODO: Cache Components adoption. Refactor this route so this opt-out can be removed.
-// See: https://nextjs.org/docs/app/guides/migrating-to-cache-components
-export const instant = false;
-
 export default async function TwoFactorPage({
 	searchParams,
 }: {

src/app/(site)/settings/page.tsx

@@ -10,10 +10,6 @@ import { db, User } from "@/lib/db";
 import { avatarImageUrl } from "@/lib/format";
 import { siteSettings } from "@/lib/services/site-settings";
 
-// TODO: Cache Components adoption. Refactor this route so this opt-out can be removed.
-// See: https://nextjs.org/docs/app/guides/migrating-to-cache-components
-export const instant = false;
-
 export default async function SettingsPage() {
 	const t = await getTranslations("pages.settings");
 	const session = await auth();

src/app/(site)/settings/sessions/page.tsx

@@ -7,10 +7,6 @@ import { auth } from "@/lib/auth";
 import { db, WebsiteLoginLogs } from "@/lib/db";
 import { formatDate } from "@/lib/format-date";
 
-// TODO: Cache Components adoption. Refactor this route so this opt-out can be removed.
-// See: https://nextjs.org/docs/app/guides/migrating-to-cache-components
-export const instant = false;
-
 type SearchParams = Promise<{ signedOutAll?: string }>;
 
 /** Tiny user-agent → "Browser on OS" summary (no dependency). */