feat: Transform HookLab to OBC Maçonnerie showcase site

Complete transformation of the Next.js project into a professional
showcase site for OBC Maçonnerie (Benoît Colin, maçon in Nord 59).

Key changes:
- Remove all HookLab/Sanity/Supabase/Stripe/admin/training infrastructure
- Full OBC Maçonnerie identity: logo, colors, contact info, SIREN
- Schema.org LocalBusiness structured data for Benoît Colin
- SEO metadata for all pages targeting Nord 59 keywords

New pages created (23 total):
- Home page with 10 sections (hero, services, pillars, partners,
  zone, realisations, testimonials, FAQ, contact form, footer)
- Service pages: construction-maison, renovation, assainissement,
  creation-acces, demolition, services
- Secondary pages: realisations, partenaires, contact
- Blog: listing + 6 SEO articles with static content
- 8 local SEO pages: Orchies, Douai, Valenciennes, Mouchin,
  Flines-lès-Raches, Saint-Amand-les-Eaux
- Legal pages: mentions-legales, cgv, confidentialite (OBC adapted)

Components:
- Navbar with OBC branding + mobile menu
- Footer with dark navy theme, services + navigation links
- ContactForm client component (devis request)
- LocalSEOPage reusable component for local SEO pages
- CookieBanner updated with OBC cookie key

Config:
- layout.tsx: OBC metadata, Schema.org, no Sanity CDN
- globals.css: stone color variables added
- next.config.ts: removed Sanity CDN remotePatterns
- sitemap.ts: all 30 OBC pages
- robots.ts: allow all except /api/
- api/contact/route.ts: OBC devis email template

https://claude.ai/code/session_01Uec4iHjcPwB1pU41idWEdF

app/robots.ts

@@ -1,6 +1,6 @@
 import type { MetadataRoute } from "next";
 
-const BASE_URL = process.env.NEXT_PUBLIC_APP_URL || "https://hooklab.eu";
+const BASE_URL = process.env.NEXT_PUBLIC_APP_URL || "https://obc-maconnerie.fr";
 
 export default function robots(): MetadataRoute.Robots {
   return {
@@ -8,7 +8,7 @@ export default function robots(): MetadataRoute.Robots {
       {
         userAgent: "*",
         allow: "/",
-        disallow: ["/admin/", "/api/", "/setup-admin/", "/dashboard/", "/profil/", "/formations/", "/login/", "/register/", "/candidature/"],
+        disallow: ["/api/"],
       },
     ],
     sitemap: `${BASE_URL}/sitemap.xml`,