Branche le formulaire de contact sur Resend

- Envoi reel via le SDK Resend dans app/actions/contact.ts (avec gestion d'erreur)
- Cles/adresses lues depuis l'env (RESEND_API_KEY, CONTACT_TO_EMAIL, CONTACT_FROM_EMAIL)
- Ajout de resend en dependance + lock synchronise
- .env.example documente la config (autorise dans .gitignore)
- README + TODO a jour

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

README.md

@@ -42,8 +42,14 @@ scripts/        One-off build scripts (favicon generation)
 
 ## Configuration
 
+Copy `.env.example` to `.env.local` and fill in the values.
+
 - **Site URL** — set `NEXT_PUBLIC_SITE_URL` per environment (used by metadata, sitemap,
   robots, RSS and JSON-LD). Defaults to `https://highlandgamesstudio.com` — see `lib/site.ts`.
+- **Contact form (Resend)** — the contact form sends email via [Resend](https://resend.com).
+  Set `RESEND_API_KEY`, `CONTACT_TO_EMAIL` (who receives messages) and `CONTACT_FROM_EMAIL`
+  (sender, must be on a domain verified in Resend). Without these, the form returns a
+  friendly error instead of sending. See `app/actions/contact.ts`.
 
 ## Adding a devblog post
 
@@ -70,5 +76,5 @@ PM2 process. Requires the `SSH_*` repository secrets.
 
 ## Known TODOs
 
-- Wire the contact and newsletter forms to a real email provider (currently log-only).
+- Wire the newsletter form to a real email provider (contact form now uses Resend).
 - Replace placeholder content (game, team members, social links).