Add custom fields + warranty plugin, rework settings into two-pane shell

Feature work from the 2026-07 session:

Settings IA
- Replace the flat 27-card settings hub with a persistent two-pane shell
  (SettingsLayout.vue): grouped, searchable left rail + content pane.
- Nest all settings/* routes under the shell via router post-processing;
  shared nav catalog in settingsNav.js. Group by asset class (PCs, Printers,
  Equipment, Network) so per-type settings stop scattering.

Custom fields (core)
- customfields + customfieldvalues tables (migration 7d14), CRUD API at
  /api/customfields, per-asset value get/save.
- Settings management page + reusable CustomFieldsSection (detail) and
  CustomFieldsInputs (form) wired into all four asset types.

Warranty (new plugin)
- plugins/warranty: warranties + warrantyassets (migration 7d15), derived
  coverage status, provider abstraction (manual now; Dell/Lenovo/HP stubs).
- API CRUD + per-asset panel + report buckets; WarrantyPanel on all four
  detail pages; Warranties management page; Warranty report + Reports card.
- Seed warranty.* permissions.

Printer drivers
- printerdrivers table (migration 7d13) linked to printer models; drivers now
  surface on the matching printer's detail page.

Other
- PCDetail rebalanced (Network + Status + Warranty + custom fields on the right).
- Rename PCs list "Features" column to "Remote Access"; fix badge hover underline.
- Drop equipment islocationonly field.
- Centralize asset-type label/route maps into utils/assetTypes.js.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/views/notifications/NotificationsList.vue

@@ -1,7 +1,10 @@
 <template>
   <div class="page-header">
     <h1>Notifications</h1>
-    <router-link to="/notifications/new" class="btn btn-primary">New Notification</router-link>
+    <div class="actions">
+      <router-link to="/settings/notificationtypes" class="btn btn-secondary">Manage Types</router-link>
+      <router-link to="/notifications/new" class="btn btn-primary">New Notification</router-link>
+    </div>
   </div>
 
   <div class="filters">
@@ -45,7 +48,7 @@
         <tbody>
           <tr v-for="notification in notifications" :key="notification.notificationid">
             <td>
-              <router-link :to="`/notifications/${notification.notificationid}`">
+              <router-link :to="`/notifications/${notification.notificationid}/edit`">
                 {{ notification.title }}
               </router-link>
               <span v-if="notification.ispinned" class="badge badge-primary" title="Pinned">Pinned</span>