feat(api-docs): extract API docs viewer into standalone module

Move the Swagger UI viewer from core (pages/admin/api-docs/) into
modules/api-docs/ as a self-contained module. Create module manifest
with routes, permission, sidebar.admin_nav_item slot, asset group,
and authorization policy. Remove API docs ability from core
OperationsAuthorizationPolicy and UiCapabilityMap. Remove hardcoded
sidebar nav item — now contributed via module slot. Add
admin-automation group meta to sidebar template for module nav items.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config/assets.php

@@ -58,9 +58,6 @@ return [
             'page-layout' => [
                 'css/layout/app-page-layout.css',
             ],
-            'api-docs' => [
-                'css/vendor-overrides/swagger-ui.css',
-            ],
             'docs' => [
                 'css/pages/app-docs.css',
             ],