feat(web): import oh-my-openagent-web Next.js + Cloudflare Workers site

Imports the public marketing site previously living in
../oh-my-opencode-web. Independent of the npm plugin: own package.json,
bun.lock, tsconfig.json. Not included in the published package — root
files: array still only ships dist/, bin/, postinstall.mjs.

Stack:
- Next.js 15.5 App Router + RSC, deployed to Cloudflare Workers via
  @opennextjs/cloudflare (build target .open-next/worker.js).
- Tailwind v4 + shadcn/ui primitives.
- next-intl with 4 locales (en/ja/ko/zh) under app/[locale]/.
- Playwright e2e tests under web/e2e/.
- Custom domains ohmyopenagent.com (primary) and ohmyopencode.org
  (legacy alias) declared in web/wrangler.toml.

Source files were re-formatted via `bun run format` to bring them in
line with the existing .prettierrc (singleQuote: false). Functional code
unchanged.

web/app/manifest.ts

@@ -0,0 +1,21 @@
+import type { MetadataRoute } from "next"
+
+export default function manifest(): MetadataRoute.Manifest {
+  return {
+    name: "Oh My OpenAgent",
+    short_name: "OMO",
+    description:
+      "The Best Agent Harness. Meet Sisyphus: The batteries-included agent that codes like you.",
+    start_url: "/",
+    display: "standalone",
+    background_color: "#0a0a0a",
+    theme_color: "#00d4ff",
+    icons: [
+      {
+        src: "/icon.svg",
+        sizes: "any",
+        type: "image/svg+xml",
+      },
+    ],
+  }
+}