Fix 'dubious ownership' error in update script

pct exec runs as root while /opt/linkvault is owned by the linkvault
user, so newer git versions refuse to operate on it. Mark the
directory as safe before running git pull.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/proxmox/update-linkvault.sh

@@ -30,6 +30,7 @@ fi
 echo "==> Aktualisiere LinkVault in Container $CTID..."
 pct exec "$CTID" -- bash -c "
 set -euo pipefail
+git config --global --add safe.directory /opt/linkvault
 cd /opt/linkvault
 
 if [ -n '${GIT_TOKEN}' ]; then