slides: add /screensaver route for the shopfloor slide surface

TVDashboard hardcoded surface=lobby, so only the lobby display was reachable.
Read the surface from route meta (/screensaver -> shopfloor) or a ?surface=
query, defaulting to lobby. Adds a /screensaver toplevel route so the shopfloor
screensaver surface can be displayed on a kiosk.

plugins/slides/frontend/routes.js

@@ -13,6 +13,12 @@ export const toplevel = [
     path: '/tv',
     name: 'tv',
     component: () => import('./views/TVDashboard.vue'),
-    meta: { plugin: 'slides' }
+    meta: { plugin: 'slides', surface: 'lobby' }
+  },
+  {
+    path: '/screensaver',
+    name: 'screensaver',
+    component: () => import('./views/TVDashboard.vue'),
+    meta: { plugin: 'slides', surface: 'shopfloor' }
   }
 ]

plugins/slides/frontend/views/TVDashboard.vue

@@ -27,9 +27,18 @@
 
 <script setup>
 import { ref, computed, onMounted, onUnmounted } from 'vue'
+import { useRoute } from 'vue-router'
 import api from '@/api'
 import { withBase } from '@/utils/basePath'
 
+// Which slide surface this display renders: 'lobby' (default) or 'shopfloor'
+// (the screensaver). Set by the route meta (/screensaver) or a ?surface= query.
+const route = useRoute()
+const VALID_SURFACES = ['lobby', 'shopfloor']
+const surface = (VALID_SURFACES.includes(route.meta?.surface) && route.meta.surface)
+  || (VALID_SURFACES.includes(route.query?.surface) && route.query.surface)
+  || 'lobby'
+
 const INTERVAL = 10 // seconds between slides
 
 const slides = ref([])
@@ -68,12 +77,12 @@ onUnmounted(() => {
 async function fetchSlides() {
   try {
     // Flat feed shape: { success, surface, basepath, interval, slides:[...] }
-    const response = await api.get('/slides/feed', { params: { surface: 'lobby' } })
+    const response = await api.get('/slides/feed', { params: { surface } })
     const data = response.data
 
     if (data.success && data.slides?.length > 0) {
       slides.value = data.slides
-      basePath.value = data.basepath || '/api/slides/img/lobby/'
+      basePath.value = data.basepath || `/api/slides/img/${surface}/`
       error.value = ''
 
       // Restart slideshow if slides changed