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>

modules/api-docs/pages/api-docs/spec().php

@@ -0,0 +1,29 @@
+<?php
+
+use MintyPHP\Module\ApiDocs\ApiDocsAuthorizationPolicy;
+use MintyPHP\Support\Guard;
+
+define('MINTY_ALLOW_OUTPUT', true);
+
+Guard::requireLogin();
+Guard::requireAbilityOrForbidden(ApiDocsAuthorizationPolicy::ABILITY_VIEW);
+
+$specPath = defined('APP_ROOT') ? APP_ROOT . '/docs/openapi.yaml' : dirname(__DIR__, 4) . '/docs/openapi.yaml';
+
+if (!is_file($specPath)) {
+    http_response_code(404);
+    return;
+}
+
+if (!is_readable($specPath)) {
+    http_response_code(500);
+    return;
+}
+
+header('Content-Type: application/yaml; charset=utf-8');
+header('X-Content-Type-Options: nosniff');
+header('Cache-Control: private, max-age=60');
+$bytes = @readfile($specPath);
+if ($bytes === false) {
+    http_response_code(500);
+}