Wire operator Integrations page + capability-gating framework

Completes the arcadia-admin operator surface for the integration registry and
the capability/route-guard framework it depends on.

- Integration registry: route + Data-group nav entry + `platform.integrations`
  capability; the in-app client now delegates to the shared
  `@crema/integration-registry-client` lib (vite alias + tsconfig); the
  operator Integrations page (committed earlier) is now reachable.
- Capability gating: capabilities map + route-guard + jwt helpers + the
  apps/plan/entitlements routes and supporting tenants/session changes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tsconfig.json

@@ -28,6 +28,8 @@
       "@crema/action-bus/*": ["../lib-action-bus/src/*"],
       "@crema/arcadia-client": ["../lib-arcadia-client/src/index.tsx"],
       "@crema/arcadia-client/*": ["../lib-arcadia-client/src/*"],
+      "@crema/integration-registry-client": ["../lib-integration-registry-client/src/index.tsx"],
+      "@crema/integration-registry-client/*": ["../lib-integration-registry-client/src/*"],
       "@crema/arcadia-auth-ui": ["../lib-arcadia-auth-ui/src/index.tsx"],
       "@crema/arcadia-auth-ui/*": ["../lib-arcadia-auth-ui/src/*"],
       "@crema/table-ui": ["../lib-table-ui/src/index.tsx"],