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>

tests/conftest.py

@@ -82,3 +82,35 @@ def auth_headers(client, admin_user):
     payload = response.get_json()
     token = payload['data']['access_token']
     return {'Authorization': f'Bearer {token}'}
+
+
+@pytest.fixture
+def member_user(db):
+    """Create an authenticated user with NO roles/permissions.
+
+    Username 'testmember', password 'testpass'. Used to prove that
+    authentication alone does not grant write access (authorization gating).
+    """
+    from shopdb.core.models import User
+
+    user = User(
+        username='testmember',
+        email='member@test.local',
+        passwordhash=generate_password_hash('testpass'),
+    )
+    db.session.add(user)
+    db.session.commit()
+
+    return user
+
+
+@pytest.fixture
+def member_headers(client, member_user):
+    """Log in as member_user (no roles) and return Authorization headers."""
+    response = client.post(
+        '/api/auth/login',
+        json={'username': 'testmember', 'password': 'testpass'},
+    )
+    assert response.status_code == 200, f'Login failed: {response.get_json()}'
+    token = response.get_json()['data']['access_token']
+    return {'Authorization': f'Bearer {token}'}