Archive and disable Snipcart integration for Shopify migration

Disable Snipcart e-commerce integration to prepare for Shopify Buy Button. All Snipcart code is preserved in assets/snipcart-archive/ with complete restoration instructions.

Changes:
- Comment out Snipcart SCSS import
- Disable Snipcart routes (validate.json, webhook)
- Comment Snipcart attributes in product template
- Remove Snipcart scripts from footer
- Create archive with snipcart.js, product-size.js, _snipcart.scss
- Add comprehensive README.md with restoration guide

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

site/config/config.php

@@ -37,6 +37,8 @@ return [
     ],
 
     'routes' => [
+        // SNIPCART ROUTES - Désactivées, voir assets/snipcart-archive/README.md pour restauration
+        /*
         [
             'pattern' => '(:any)/validate.json',
             'method' => 'GET',
@@ -144,5 +146,6 @@ return [
                 return Response::json(['status' => 'success'], 200);
             }
         ]
+        */
     ]
 ];