ADR-013 Phase 4: relocate 4 self-contained plugin frontends

Relocate applications, geenforce, knowledgebase, and machines - each owns only
its own views dir, so a clean move to plugins/<name>/frontend/ (views/ +
routes.js, core imports rewritten to @/). geenforce's entryForm.js helper + its
vitest spec move with it (ManifestEditor imports it as a sibling).

Machinery fixes this batch surfaced:
- routes.gen.js codegen uses namespace imports (import * as p_x). A route file
  without a `toplevel` export is undefined on the namespace instead of a strict-
  ESM missing-binding build error.
- vitest gains a `pretest` stage so plugin-frontend specs (now under
  plugins/<name>/frontend/) run from their staged copy in src/.plugins-staged/.

Verified live: GE-Enforce (the most complex, uses the entryForm sibling helper)
renders fully from its staged frontend. Build + 58 vitest + naming green.

plugins/knowledgebase/frontend/routes.js

@@ -0,0 +1,29 @@
+/**
+ * Knowledge Base plugin routes
+ */
+export default [
+  {
+    path: 'knowledgebase',
+    name: 'knowledgebase',
+    component: () => import('./views/KnowledgeBaseList.vue'),
+    meta: { plugin: 'knowledgebase' }
+  },
+  {
+    path: 'knowledgebase/new',
+    name: 'knowledgebase-new',
+    component: () => import('./views/KnowledgeBaseForm.vue'),
+    meta: { requiresAuth: true, plugin: 'knowledgebase' }
+  },
+  {
+    path: 'knowledgebase/:id',
+    name: 'knowledgebase-detail',
+    component: () => import('./views/KnowledgeBaseDetail.vue'),
+    meta: { plugin: 'knowledgebase' }
+  },
+  {
+    path: 'knowledgebase/:id/edit',
+    name: 'knowledgebase-edit',
+    component: () => import('./views/KnowledgeBaseForm.vue'),
+    meta: { requiresAuth: true, plugin: 'knowledgebase' }
+  }
+]