feat(admin): open controller-link settings entries from the settings index

A settings entry with a controller opens that controller's route from
its card (settingsPath); singleton cards still open /settings/<code>.
On a linked controller with no navigation entry of its own the rail
marks Settings current, the breadcrumbs read Settings > entry label
(plus the record title on record and create routes) and the page title
uses the entry label. The settings docs describe the admin behaviour;
the embedded admin shell is rebuilt.

admin/src/views/SettingsIndexView.vue

@@ -2,10 +2,11 @@
 import { RouterLink } from 'vue-router'
 import { t } from '../app/i18n'
 import { iconFor } from '../app/icons'
-import { settingsGroups } from '../state/useSettings'
+import { settingsGroups, settingsPath } from '../state/useSettings'
 
 // Settings index (D-21): every permitted settings page, grouped by category,
-// with its icon, label and description. The server filters the list.
+// with its icon, label and description. The server filters the list. A
+// singleton entry opens its settings form; a link entry opens its controller.
 </script>
 
 <template>
@@ -27,7 +28,7 @@ import { settingsGroups } from '../state/useSettings'
         <RouterLink
           v-for="entry in group.entries"
           :key="entry.code"
-          :to="`/settings/${encodeURIComponent(entry.code)}`"
+          :to="settingsPath(entry)"
           :data-settings="entry.code"
           class="flex items-start gap-3.5 rounded-card border border-border bg-surface p-5 text-text no-underline shadow-card hover:bg-hover"
         >