Update RSVP date format and enhance invite page styles

Changed the RSVP deadline format to "dd.MM.yyyy" for consistency. Improved text styles by adding bold fonts to emphasize key sections and included a new confirmation message for RSVP deadline.

frontend/src/app/(public)/invite/[slug]/page.tsx

@@ -101,7 +101,7 @@ const InvitationPage = () => {
 
   // Format RSVP deadline
   const rsvpDeadline = event.rsvp_deadline
-    ? format(parseISO(event.rsvp_deadline), "MMMM d, yyyy")
+    ? format(parseISO(event.rsvp_deadline), "dd.MM.yyyy")
     : null;
 
   // Get asset URLs
@@ -363,7 +363,7 @@ const InvitationPage = () => {
                   {event.description}
                 </div>
                 <p
-                  className="mt-4 text-center text-sm italic sm:text-base"
+                  className="mt-4 font-bold text-center text-sm italic sm:text-base"
                   style={{ color: colors.secondary }}
                 >
                   Con affetto, Emma, Anto & Fely
@@ -371,7 +371,12 @@ const InvitationPage = () => {
               </div>
             </motion.div>
           )}
-
+          <p
+            className="mb-2 text-sm font-medium sm:text-base"
+            style={{ color: colors.text }}
+          >
+            Conferma partecipazione entro {rsvpDeadline}
+          </p>
           {/* RSVP and Gift Registry Section */}
           <motion.div
             variants={itemVariants}