GE-Enforce polish: DDL-parity guard test, retire Collector PC Types page

Add test_geenforce_ddl_parity to lock the manifest models against their
Alembic baseline (catches model/migration drift for a chain that is still
amendable pre-deploy).

Retire the "Collector PC Types" settings card: GE-Enforce scope
computertypeid supersedes the pctypemap editor UI (ADR-012). The collector
still reads pctype_mapping(), so the backend map stays; only the editor
surface is removed, with a deprecation note in pctypemap.py.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/settings/settingsNav.js

@@ -92,7 +92,6 @@ export const settingsGroups = [
       { to: '/settings/servicenow', icon: Link, title: 'ServiceNow', description: 'ServiceNow ticket links (incident, change) prefixes and global-search redirect' },
       { to: '/settings/zabbix', icon: Droplets, title: 'Zabbix Supplies', description: 'Zabbix API for real-time printer toner and supply monitoring' },
       { to: '/settings/dellwarranty', icon: ShieldCheck, title: 'Dell Warranty', description: 'Dell TechDirect warranty API lookup by service tag' },
-      { to: '/settings/pctypemapping', icon: Laptop, title: 'Collector PC Types', description: 'Map collector enrollment imaging pc-type (shopfloor) to a Computer Type' },
     ],
   },
   {