feat(website): add og:title and og:description via pageMeta helper

Extract a DRY pageMeta(title, description) helper that returns both
standard and OpenGraph meta tags from a single source of truth.

packages/website/src/routes/opencode.tsx

@@ -1,16 +1,13 @@
 import { createFileRoute } from '@tanstack/react-router'
 import { LandingPage } from '~/components/landing-page'
+import { pageMeta } from '~/meta'
 
 export const Route = createFileRoute('/opencode')({
   head: () => ({
-    meta: [
-      { title: 'OpenCode Mobile App – Code from anywhere | Paseo' },
-      {
-        name: 'description',
-        content:
-          'Run OpenCode from your phone. Launch agents, watch them work, and ship code from wherever you are. Self-hosted, open source, your code stays local.',
-      },
-    ],
+    meta: pageMeta(
+      'OpenCode Mobile App – Code from anywhere | Paseo',
+      'Run OpenCode from your phone. Launch agents, watch them work, and ship code from wherever you are. Self-hosted, open source, your code stays local.',
+    ),
   }),
   component: OpenCodePage,
 })