Fix hreflang canonical + LangToggle: use centralized ES/EN slug map

- Add src/i18n/hreflang-map.ts with getHreflangUrl() for translated slugs
- Fix BaseLayout.astro hreflang tags (was hardcoding ES='/', 404 URLs)
- Fix LangToggle.astro to use hreflang map instead of naive path swap
- Fix htaccess.conf: remove !-f / !-d that blocked .html redirects

scripts/htaccess.conf

@@ -12,9 +12,7 @@
   RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
   RewriteRule ^(.*)$ https://%1/$1 [R=301,L]
 
-  # Quitar .html de la URL (limpieza opcional)
-  RewriteCond %{REQUEST_FILENAME} !-f
-  RewriteCond %{REQUEST_FILENAME} !-d
+  # Quitar .html de la URL — evita duplicados index.html vs /
   RewriteCond %{REQUEST_URI} ^(.+)\.html$ [NC]
   RewriteRule ^(.+)\.html$ /$1 [R=301,L]
 </IfModule>