Add Storage, Users, Secrets, Webhooks, Scheduled tasks, Audit log screens

Full management surfaces for the platform-admin tenant, mirroring the
existing Tenants pattern (DataTable + row actions + create/edit dialogs +
ConfirmDialog for destructive ops, all data-action tagged for the
command bus, useRegisterAdminContext publishing for the assistant).

- Storage (/storage): backends + credentials. Write-only secret fields,
  Validate/Activate/Deactivate/Set-default/Mark-degraded/Maintenance.
- Users (/users): tabs for Users, Invitations, Roles. Per-user View
  drawer with profile, role add/remove, API keys (one-time reveal on
  create), usage + quota.
- Secrets (/secrets): /api/v1/admin/secrets — create/rotate/rollback,
  versions dialog, enable/disable, generate-value helper.
- Webhooks (/webhooks): CRUD, pause/resume, regenerate-secret with
  one-time reveal, send test event, deliveries dialog.
- Scheduled tasks (/scheduled-tasks): cron CRUD, run-now trigger,
  enable/disable, expandable run history.
- Audit log (/activity): replaces the empty stub. Filter by severity,
  resource type, date range; click for full JSON detail.

All endpoints are hand-rolled HTTP because most aren't covered by the
generated OpenAPI typed paths yet — switch to arcadia.typed.* when the
backend wires them into OpenApiSpex.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/routes.ts

@@ -11,5 +11,10 @@ export default [
   route("profile", "routes/profile.tsx"),
   route("login", "routes/login.tsx"),
   route("tenants", "routes/tenants.tsx"),
+  route("storage", "routes/storage.tsx"),
+  route("users", "routes/users.tsx"),
+  route("secrets", "routes/secrets.tsx"),
+  route("webhooks", "routes/webhooks.tsx"),
+  route("scheduled-tasks", "routes/scheduled-tasks.tsx"),
   // CREMA:ROUTES
 ] satisfies RouteConfig