Lean build: gate Shopfloor Dashboard on the notifications plugin

Shopfloor Dashboard is a core view but its content is entirely
notificationsApi.getShopfloor() + the calendar (both owned by the notifications
plugin). Without notifications the display is empty, so gate the Displays link
on the notifications/calendar route being staged. On a site without it the link
- and the Displays header when nothing else is present - drops.

frontend/src/views/AppLayout.vue

@@ -25,7 +25,7 @@
         </template>
 
         <div v-if="showDisplays" class="nav-section">Displays</div>
-        <a v-if="hasRoute('/shopfloor')" :href="withBase('/shopfloor')" target="_blank" class="external-link">Shopfloor Dashboard</a>
+        <a v-if="showShopfloor" :href="withBase('/shopfloor')" target="_blank" class="external-link">Shopfloor Dashboard</a>
         <a v-if="hasRoute('/tv')" :href="withBase('/tv')" target="_blank" class="external-link">TV Slideshow</a>
         <a v-if="hasRoute('/parts-kiosk')" :href="withBase('/parts-kiosk')"
            target="_blank" class="external-link">Parts Kiosk</a>
@@ -124,7 +124,12 @@ const authStore = useAuthStore()
 // report for a plugin that was never staged.
 const stagedRoutePaths = new Set(router.getRoutes().map(r => r.path))
 const hasRoute = (path) => stagedRoutePaths.has(path)
-const showDisplays = ['/shopfloor', '/tv', '/parts-kiosk'].some(hasRoute)
+// Shopfloor Dashboard is a core view but runs entirely on the notifications
+// plugin (notificationsApi.getShopfloor + the calendar); without it the display
+// is empty, so gate the link on the notifications plugin being in this build.
+const showShopfloor = hasRoute('/shopfloor')
+  && (hasRoute('/notifications') || hasRoute('/calendar'))
+const showDisplays = showShopfloor || hasRoute('/tv') || hasRoute('/parts-kiosk')
 const routeViewKey = computed(() =>
   route.path.startsWith('/settings') ? '/settings' : route.path
 )