def unread_notifications_count(request):
    """
    Injecte le nombre de notifications non lues dans tous les templates.
    Disponible via la variable {{ unread_notifications_count }}.
    """
    if not request.user.is_authenticated:
        return {'unread_notifications_count': 0}
    try:
        from .services import get_unread_count
        count = get_unread_count(request.user)
    except Exception:
        count = 0
    return {'unread_notifications_count': count}