Remove next/cache usage (use cache, cacheLife, cacheTag, cacheComponents)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01F22Ms5Cxam5UHyxaCrtZzu

app/layout.tsx

@@ -8,8 +8,8 @@ import { SITE_ORIGIN } from "@/lib/site";
 import { AppShell } from "./app-shell";
 
 /**
- * Root layout (engineering.md F1, F4, F7, F10). With `cacheComponents: true`,
- * the layout is a **static shell** — it prerenders the `<html>`/`<body>` +
+ * Root layout (engineering.md F1, F4, F7, F10). The layout is a
+ * **static shell** — it prerenders the `<html>`/`<body>` +
  * announcement bar, then wraps the per-request (dynamic) `AppShell` (cart seed
  * + analytics shop + chrome) in `<Suspense>` so the dynamic parts stream while
  * the static shell serves immediately. `AppShell` calls `connection()` to opt