fix(brand): Memento (not Momento) — fix typo + add link to memento-note.com

The product name is 'Memento' (not 'Momento'). The 'Momento' typo was
present in 12 i18n locale files (en, fr, es, de, it, pt, nl, ja, ko,
zh, ru, ar, fa) and in code comments.

Also added a 'memento.url' i18n key with the canonical link
https://memento-note.com/ and wrapped the Memento promo cards in
both DashboardSidebar.tsx and translate/page.tsx with an <a> tag
pointing to that URL. Previously the cards were a non-clickable
<div>, so users had no way to reach the Memento product page.

Note: 'momento' is a legitimate word in Italian, Spanish and
Portuguese meaning 'moment' (e.g. 'a qualsiasi momento'). Those
occurrences in pricing.json and services.json were NOT changed —
they are correct translations of UI strings about 'at any moment'.

frontend/src/app/dashboard/DashboardSidebar.tsx

@@ -68,8 +68,13 @@ export function DashboardSidebar() {
         </div>
       )}
 
-      {/* Momento promo section */}
-      <div className="px-6 py-4">
+      {/* Memento promo section */}
+      <a
+        href={t('memento.url', { defaultValue: 'https://memento-note.com/' })}
+        target="_blank"
+        rel="noopener noreferrer"
+        className="block px-6 py-4"
+      >
         <div className="bg-brand-muted/50 dark:bg-[#1f1f1f]/50 rounded-3xl p-6 border border-black/5 dark:border-white/5 group cursor-pointer hover:bg-brand-dark dark:hover:bg-brand-accent transition-all duration-500">
           <div className="flex items-center gap-3 mb-4">
             <div className="w-8 h-8 bg-brand-dark group-hover:bg-brand-accent rounded-lg flex items-center justify-center text-white text-xs font-black shadow-sm transition-all group-hover:rotate-12">M</div>
@@ -82,7 +87,7 @@ export function DashboardSidebar() {
             {t('memento.ctaFree')}
           </button>
         </div>
-      </div>
+      </a>
 
       {/* User section */}
       <div className="border-t border-black/5 dark:border-white/5">