fix(seo): self-canonical + unique description on 6 pages that deduped to home

contact / careers / status / privacy / terms / docs set no alternates, so they
inherited the layout's canonical (= the locale homepage) — Google treats them as
duplicates of the home page and drops them. Each now sets a self-referencing
canonical + full fa/en/x-default hreflang (new shared lib/seo.ts pageAlternates)
and a unique meta description (added *Desc keys, fa/en) + per-page OpenGraph.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

web/website/messages/en.json

@@ -25,7 +25,13 @@
     "termsTitle": "Terms of Service — Meezi",
     "docsTitle": "Documentation & Help — Meezi",
     "statusTitle": "Service Status — Meezi",
-    "contactTitle": "Contact Us — Meezi"
+    "contactTitle": "Contact Us — Meezi",
+    "contactDesc": "Get in touch with the Meezi team — phone, email, and live chat support for cafés and restaurants.",
+    "careersDesc": "Join Meezi — we're building the smart café & restaurant management platform for Iran. See open roles.",
+    "statusDesc": "Live status of Meezi services — POS, dashboard, and APIs. Check current uptime and incidents.",
+    "privacyDesc": "How Meezi collects, uses, and protects your data. Read our privacy policy.",
+    "termsDesc": "The terms of service that govern your use of Meezi's café & restaurant management platform.",
+    "docsDesc": "Meezi help center — step-by-step guides for POS, menu, tables, inventory, staff, reports, and more."
   },
   "nav": {
     "features": "Features",