ticket-list.html y ticket-detail.html usan rutas incorrectas. El layout está en templates/layout/
<!-- Así están ahora -->
<head th:replace="~{head :: head('...')}">
<nav th:replace="~{navbar :: navbar}">
<footer th:replace="~{footer :: footer}">
<div th:replace="~{footer :: scripts}">
<!-- Cambiarlo por -->
<head th:replace="~{layout/head :: head('...')}">
<nav th:replace="~{layout/navbar :: navbar}">
<footer th:replace="~{layout/footer :: footer}">
<script th:replace="~{layout/footer :: scripts}">Afecta a: ticket-list.html, ticket-detail.html y ticket-form.html.
ticket-list.htmlyticket-detail.htmlusan rutas incorrectas. El layout está entemplates/layout/Afecta a:
ticket-list.html,ticket-detail.htmlyticket-form.html.