fix: display db timestamps in Brussels time

(heure de dépôt was showing UTC)

- feat: add date_depot column (real TFE deposit date)
with CSV round-trip + Brussels→UTC sanitization
- fix: keep PHP default tz at UTC to preserve token/share-link
 expiry consistency; convert to Brussels only in db_datetime()

justfile

@@ -376,7 +376,7 @@ deploy-backup-cron:
     @echo "📋 Installing backup cron jobs…"
     rsync -v deploy/xamxam-backup.cron xamxam:/tmp/xamxam-backup.cron
     ssh -t xamxam "sudo install -o root -g root -m 644 /tmp/xamxam-backup.cron /etc/cron.d/xamxam-backup && rm -f /tmp/xamxam-backup.cron"
-    ssh -t xamxam "sudo mkdir -p /var/backups/xamxam && sudo chown www-data:www-data /var/backups/xamxam && sudo chmod 755 /var/backups/xamxam"
+    ssh -t xamxam "sudo mkdir -p /var/backups/xamxam && sudo chown www-data:xamxam /var/backups/xamxam && sudo chmod 775 /var/backups/xamxam"
     ssh -t xamxam "sudo touch /var/log/xamxam-backup-\$(date +%Y-%m-%d).log && sudo chown www-data:www-data /var/log/xamxam-backup-\$(date +%Y-%m-%d).log && sudo chmod 644 /var/log/xamxam-backup-\$(date +%Y-%m-%d).log"
     @echo "✅ Cron jobs installed."
     @echo "   Cron file: /etc/cron.d/xamxam-backup"