Lean build: hide settings cards whose route was not staged

settingsNav.js hardcodes plugin settings (PC Access Protocols, Machine Types,
VLANs, Employee Directory, ...). A lean per-site build only stages the chosen
plugins' settings routes, so the settings rail showed cards for absent plugins
that dead-ended on a blank page. useSettingsCatalog now filters the catalog to
cards whose target route is registered in this build's router (router.getRoutes),
dropping now-empty groups. Generic - gates every settings card by staged routes
with no per-plugin logic; full builds keep every card. Found testing a live
machines+printers lean site.

frontend/src/composables/settingsCatalog.js

@@ -3,9 +3,10 @@
 // GET /api/pluginui/settings-cards. Both SettingsLayout (rail) and SettingsIndex
 // (landing) read the merged catalog so plugins add settings cards with no core
 // edit. Fetched once into a module-level ref and shared across callers.
-import { ref } from 'vue'
+import { ref, computed } from 'vue'
 import { Ruler, Wrench, Cog, Package, Settings, Puzzle, SlidersHorizontal, Palette, Bell, Network, Printer, Droplets } from 'lucide-vue-next'
 import api from '../api'
+import router from '../router'
 import { settingsGroups } from '../views/settings/settingsNav'
 
 // Icon string keys (as returned by the hook) mapped to Lucide components,
@@ -62,18 +63,36 @@ function mergeCards(baseGroups, cards) {
   return merged
 }
 
+// Drop cards whose target route is not registered in THIS build. settingsNav
+// hardcodes plugin settings (PC Access Protocols, Machine Types, VLANs, ...),
+// but a lean per-site build only stages the chosen plugins' settings routes;
+// showing a card whose route was never staged lands the admin on a blank page.
+// Filtering by the router's own route table gates every menu the same way with
+// no per-plugin logic. Called inside a computed so the (circular) router import
+// is resolved by the time it runs, and so full builds keep every card.
+function keepRegistered(baseGroups) {
+  const registered = new Set(router.getRoutes().map(r => r.path))
+  return baseGroups
+    .map(group => ({
+      title: group.title,
+      cards: group.cards.filter(card => registered.has(card.to)),
+    }))
+    .filter(group => group.cards.length)
+}
+
 // Shared across component instances: seeded with the core groups, replaced with
 // the merged catalog once the hook endpoint answers.
-const groups = ref(settingsGroups)
+const rawGroups = ref(settingsGroups)
+const groups = computed(() => keepRegistered(rawGroups.value))
 let loaded = false
 
 async function loadCatalog() {
   try {
     const response = await api.get('/pluginui/settings-cards')
-    groups.value = mergeCards(settingsGroups, response.data.data || [])
+    rawGroups.value = mergeCards(settingsGroups, response.data.data || [])
   } catch (error) {
     // Degrade to the core-only catalog; the rail still works without plugins.
-    groups.value = settingsGroups
+    rawGroups.value = settingsGroups
   }
 }