feat: add favicon, structured data & SEO optimization for Google sitelinks

- Add SVG favicon (H logo navy+orange) for all sizes (32, 180, 192, 512)
- Add web manifest (site.webmanifest) for PWA compatibility
- Add theme-color meta tag (#1B2A4A navy)
- Add 3 structured data schemas: LocalBusiness, WebSite, SiteNavigationElement
- WebSite schema enables Google to show site name + search box
- SiteNavigationElement signals main pages for sitelinks display
- Add canonical URLs to all pages (macon, paysagiste, plombier, legal pages)
- Add metadata to pages missing it (mentions-legales, confidentialite, cgv)
- Add candidature/layout.tsx for metadata on client component page
- Optimize sitemap with consistent BASE_URL and candidature/cgv pages
- Add telephone, email, opening hours to LocalBusiness schema

https://claude.ai/code/session_01V8YAjpqRQ3bfBYsABYsEgo

app/confidentialite/page.tsx

@@ -1,5 +1,15 @@
+import type { Metadata } from "next";
 import Link from "next/link";
 
+export const metadata: Metadata = {
+  title: "Politique de Confidentialité",
+  description:
+    "Politique de confidentialité et protection des données personnelles du site HookLab.eu, conformément au RGPD.",
+  alternates: {
+    canonical: "https://hooklab.eu/confidentialite",
+  },
+};
+
 export default function Confidentialite() {
   return (
     <main className="min-h-screen py-20 md:py-32">