Add homepage, tarifs, legal pages, navbar, footer and full test coverage

- Homepage: hero, how it works (buyer/organizer), features, CTA
- Tarifs: 3 plans (Gratuit, Basique 10€, Sur-mesure), JSON-LD Product
- Legal pages: mentions legales, CGU (tabs buyer/organizer), CGV, RGPD, cookies, hosting
- Navbar: neubrutalism style, logo liip, mobile menu, SEO attributes
- Footer: contact, description, legal links, tarifs
- Sitemap: add /tarifs and /sitemap-orgas-{page}.xml
- Liip Imagine: remove S3, webp format on all filters
- Tests: full coverage for all controllers, services, repositories
- Fix CSP: replace inline onclick with data-tab JS

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -16,6 +16,7 @@
 node_modules/
 .idea/
 cert/
+/public/media/
 
 ###> friendsofphp/php-cs-fixer ###
 /.php-cs-fixer.php