perf: add ISR revalidation to past events page

Add revalidate = 3600 to avoid re-fetching all events from
the Meetup API on every page visit. The page is now served from
cache and revalidated once per hour.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Slashgear

app/evenements-precedents/[year]/page.tsx

@@ -3,6 +3,8 @@ import React from 'react';
 import { Metadata } from 'next';
 import { PastEvents } from './pastEvents';
 import { fetchPastEvents } from '../../../modules/meetup/queries/past-events.api';
+export const revalidate = 3600;
+
 const DEFAULT_YEAR = `${new Date().getFullYear()}`;
 
 export default async function PastEventsPage({ params }: { params: Promise<{ year?: string }> }) {