refactor(login): unify title styling by replacing class with shared auth-title

src/app/core/layout/auth-layout/auth-layout.component.scss

@@ -23,6 +23,14 @@
   padding: 2rem 1.5rem;
 }
 
+:host ::ng-deep .auth-title {
+  margin: 0;
+  color: #666666;
+  font-size: 17px;
+  font-weight: 700;
+  text-transform: uppercase;
+}
+
 @media (min-width: 768px) {
   .auth-layout {
     padding: 3rem 0;

src/app/features/store/pages/login-page/login-page.component.html

@@ -1,5 +1,5 @@
 <header class="login-page__header text-center">
-  <h1 id="login-title" class="login-page__title">Iniciar sesión</h1>
+  <h1 id="login-title" class="auth-title">Iniciar sesión</h1>
 </header>
 
 <form class="login-page__form d-grid gap-3" novalidate aria-labelledby="login-title">

src/app/features/store/pages/login-page/login-page.component.scss

@@ -6,14 +6,6 @@
   margin-bottom: 1.5rem;
 }
 
-.login-page__title {
-  margin: 0;
-  color: #666666;
-  font-size: 17px;
-  font-weight: 700;
-  text-transform: uppercase;
-}
-
 .login-page__form {
   width: 100%;
 }