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/lib/i18n/messages/es/memento.json

@@ -1,6 +1,7 @@
 {
-  "memento.title": "Descubre Momento",
-  "memento.slogan": "Momento no es solo una aplicación de notas. Es un ecosistema inteligente que conecta, analiza y desarrolla tus ideas en tiempo real usando 6 agentes de IA y búsqueda semántica avanzada.",
+  "memento.title": "Descubre Memento",
+  "memento.slogan": "Memento no es solo una aplicación de notas. Es un ecosistema inteligente que conecta, analiza y desarrolla tus ideas en tiempo real usando 6 agentes de IA y búsqueda semántica avanzada.",
   "memento.ctaFree": "Empezar gratis",
-  "memento.ctaMore": "Saber más"
+  "memento.ctaMore": "Saber más",
+  "memento.url": "https://memento-note.com/"
 }