Add Spanish and Arabic versions, a contact form captcha and a multilingual sitemap

- English, Spanish (/es) and Arabic (/ar, right to left) versions of every page, with a language switch
- Self-hosted "I'm not a robot" check on the contact form; the message field is optional
- Google Tag Manager, GA4 and Search Console verification in the shared layout
- Sitemap, robots.txt and canonical links point at aigrowthtechnologies.com

src/content/home/index.ts

@@ -0,0 +1,7 @@
+import type { Locale } from "@/i18n/config";
+import { en, type Home } from "./en";
+import { es } from "./es";
+import { ar } from "./ar";
+
+export type { Home };
+export const home: Record<Locale, Home> = { en, es, ar };