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/warranty/services/providers.py

@@ -0,0 +1,93 @@
+"""Warranty provider abstraction.
+
+A provider looks up coverage for a unit by service tag / serial. Phase 1 ships
+manual entry plus provider stubs that read per-vendor API config from settings.
+When a real API (Dell TechDirect, Lenovo, HP) is wired later, only the matching
+provider's lookup() body changes - callers and the API surface stay the same.
+"""
+
+from shopdb.api import db
+from shopdb.core.models import Setting
+
+
+class ProviderNotConfigured(Exception):
+    """Raised when a provider is asked to look up but has no API config."""
+    pass
+
+
+def _setting(key, default=None):
+    row = Setting.query.filter_by(key=key).first()
+    return row.value if row and row.value not in (None, '') else default
+
+
+class WarrantyProvider:
+    """Base provider. name matches Warranty.provider values."""
+    name = 'base'
+
+    def lookup(self, servicetag, vendor=None):
+        """Return a dict of {servicelevel, startdate, enddate} or None.
+
+        Raises ProviderNotConfigured when the provider needs API creds it does
+        not have.
+        """
+        raise NotImplementedError
+
+
+class ManualProvider(WarrantyProvider):
+    """No external lookup - values are entered by hand."""
+    name = 'manual'
+
+    def lookup(self, servicetag, vendor=None):
+        return None
+
+
+class ApiProvider(WarrantyProvider):
+    """Common shape for vendor API providers. Reads enabled/url/token from
+    settings under warranty_<name>_*. Real HTTP call is deferred to a later
+    phase; today it fails loud if asked to look up so manual entry is unaffected.
+    """
+
+    def _config(self):
+        enabled = str(_setting(f'warranty_{self.name}_enabled', 'false')).lower() == 'true'
+        url = _setting(f'warranty_{self.name}_apiurl')
+        token = _setting(f'warranty_{self.name}_apitoken')
+        return enabled, url, token
+
+    def lookup(self, servicetag, vendor=None):
+        enabled, url, token = self._config()
+        if not (enabled and url and token):
+            raise ProviderNotConfigured(
+                f'{self.name} warranty lookup is not configured. '
+                f'Set warranty_{self.name}_enabled/apiurl/apitoken in Settings.'
+            )
+        # Phase 2+: perform the vendor API call here and map the response to
+        # {servicelevel, startdate, enddate}. Until then, signal not-yet-built.
+        raise ProviderNotConfigured(
+            f'{self.name} API lookup not implemented yet (config present).'
+        )
+
+
+class DellProvider(ApiProvider):
+    name = 'dell'
+
+
+class LenovoProvider(ApiProvider):
+    name = 'lenovo'
+
+
+class HpProvider(ApiProvider):
+    name = 'hp'
+
+
+_PROVIDERS = {p.name: p for p in (
+    ManualProvider(), DellProvider(), LenovoProvider(), HpProvider()
+)}
+
+
+def get_provider(name):
+    """Return a provider instance, defaulting to manual for unknown names."""
+    return _PROVIDERS.get((name or 'manual').lower(), _PROVIDERS['manual'])
+
+
+def provider_names():
+    return list(_PROVIDERS.keys())