feat: explain expired admin sessions

apps/web/src/pages/LoginPage.vue

@@ -1,10 +1,11 @@
 <script setup>
 import { nextTick, ref, watch } from 'vue';
-import { useRouter } from 'vue-router';
+import { useRoute, useRouter } from 'vue-router';
 
 import { useAuth } from '@/composables/useAuth.js';
 
 const router = useRouter();
+const route = useRoute();
 const { signIn, isLoading, error } = useAuth();
 const email = ref('');
 const password = ref('');
@@ -32,6 +33,7 @@ async function submit() {
     <form class="auth-panel" @submit.prevent="submit">
       <p class="catalog-kicker">Private workspace</p>
       <h1>Sign in</h1>
+      <p v-if="route.query.reason === 'session-expired'" class="state state--error" role="alert" tabindex="-1">Your session expired. Sign in again to continue.</p>
       <p class="detail-notes">Manage your collection, images, and listings.</p>
       <label class="fixture-label" for="admin-email">Email</label>
       <input id="admin-email" v-model="email" class="fixture-input" type="email" autocomplete="username" required />

apps/web/src/router/index.js

@@ -45,5 +45,5 @@ const auth = useAuth();
 router.beforeEach(async (to) => {
   if (!to.path.startsWith('/admin')) return true;
   if (!auth.isAuthenticated.value) await auth.load();
-  return auth.isAuthenticated.value ? true : { name: 'login' };
-});
+  return auth.isAuthenticated.value ? true : { name: 'login', query: { reason: 'session-expired' } };
+});

docs/IMPLEMENTATION-STATUS.md

@@ -277,6 +277,7 @@ Remaining roadmap areas are approved external provider credentials/adapters, bro
 - Login errors now move focus to the announced error message so failed authentication is immediately available to keyboard and assistive-technology users.
 - Login error focus behavior now has Storybook interaction coverage using a deterministic failed-authentication response.
 - Admin logout now exposes a busy state and disables repeat activation while the session is being revoked.
+- Expired admin sessions now redirect to login with an accessible explanation that prompts the user to sign in again.
 
 ## Local Commands