ADR-013 Phase 4: extract the 11 plugin routes embedded in core.js

core.js still routed plugin-owned pages directly. Extracted all 11 into the
owning plugin's route file + moved their views into plugins/<name>/frontend/:
- computers: reports/pc-relationships, settings/pctypemapping
- printers: reports/toner, settings/printertypes, settings/zabbix (toner/supply
  monitoring)
- machines: settings/machinetypes
- network: settings/networktypes
- warranty: settings/dellwarranty
- slides: settings/slides (its route file gains a default export; it was
  toplevel-only)
- employees: NEW plugin frontend (employees/:sso + settings/employeedirectory) -
  employees had no route file before; its pages lived only in core.js.

core.js now holds only core routes; all 14 bundled plugins are self-contained
under plugins/<name>/frontend/. Verified live: the extracted Machine Types
settings page renders in the settings rail from the machines plugin frontend.
Build + 58 vitest + naming green.

plugins/computers/frontend/routes.js

@@ -2,6 +2,18 @@
  * Computers plugin routes
  */
 export default [
+  {
+    path: 'reports/pc-relationships',
+    name: 'report-pc-relationships',
+    component: () => import('./views/PCRelationshipsReport.vue'),
+    meta: { plugin: 'computers' }
+  },
+  {
+    path: 'settings/pctypemapping',
+    name: 'pctype-mapping-settings',
+    component: () => import('./views/PCTypeMappingSettings.vue'),
+    meta: { requiresAuth: true, requiresAdmin: true, plugin: 'computers' }
+  },
   {
     path: 'pcs',
     name: 'pcs',