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>

plugins/slides/plugin.py

@@ -15,6 +15,7 @@ from flask import Flask, Blueprint
 from shopdb.plugins.base import BasePlugin, PluginMeta
 
 from .api import slides_bp
+from .models import TvSlide
 
 logger = logging.getLogger(__name__)
 
@@ -54,8 +55,19 @@ class SlidesPlugin(BasePlugin):
         return slides_bp
 
     def get_models(self) -> List[Type]:
-        """No models - slides are read from the filesystem."""
-        return []
+        """Slide playlist metadata (image files live on disk)."""
+        return [TvSlide]
+
+    def get_navigation_items(self) -> List[Dict]:
+        """Sidebar entry for the slide manager (admin)."""
+        return [
+            {
+                'name': 'Slides',
+                'icon': 'image',
+                'route': '/settings/slides',
+                'position': 7,
+            },
+        ]
 
     def init_app(self, app: Flask, db_instance) -> None:
         """Initialize plugin with Flask app."""