refactor(system-info): reduce to Stripe-style status page

Reduce admin/system-info to a single focused status view: overall
status banner, components list from existing health checks, and an
environment meta table. Drops the Modules and Permissions tabs —
those were dev-diagnostics already available via CLI.

- Remove SystemInfoService + its test; wire the action directly to
  SystemHealthService and build meta inline
- Extend SystemHealthService with per-check label + description so
  the UI speaks in customer terms while the CLI doctor path stays
  compatible
- Rebuild the view on existing app-stats-table + app-empty-state
  primitives; add a small app-status-banner component for the
  headline signal
- Align help-center nav label and i18n keys (de/en)

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

pages/admin/system-info/index().php

@@ -2,20 +2,44 @@
 
 use MintyPHP\Buffer;
 use MintyPHP\Service\Access\OperationsAuthorizationPolicy;
-use MintyPHP\Service\System\SystemInfoService;
+use MintyPHP\Service\System\SystemHealthService;
 use MintyPHP\Support\Guard;
 
 Guard::requireAbilityOrForbidden(OperationsAuthorizationPolicy::ABILITY_ADMIN_SYSTEM_INFO_VIEW);
 
-$pageData = app(SystemInfoService::class)->buildPageData();
-$overview = $pageData['overview'] ?? [];
-$modules = $pageData['modules'] ?? [];
-$permissions = $pageData['permissions'] ?? [];
-$healthChecks = $overview['health_checks'] ?? [];
+$checks = app(SystemHealthService::class)->runAll();
 
-Buffer::set('title', t('System Info'));
+$overall = 'ok';
+foreach ($checks as $check) {
+    if ($check['status'] === 'fail') {
+        $overall = 'fail';
+        break;
+    }
+    if ($check['status'] === 'warn') {
+        $overall = 'warn';
+    }
+}
+
+$environment = 'unknown';
+if (defined('APP_ENV')) {
+    $environment = (string) constant('APP_ENV');
+} else {
+    $envVar = getenv('APP_ENV');
+    if (is_string($envVar) && $envVar !== '') {
+        $environment = $envVar;
+    }
+}
+
+$meta = [
+    'php_version' => PHP_VERSION,
+    'environment' => $environment,
+];
+
+$lastChecked = date('Y-m-d H:i:s');
+
+Buffer::set('title', t('System status'));
 
 $breadcrumbs = [
     ['label' => t('Home'), 'path' => 'admin'],
-    ['label' => t('System Info')],
+    ['label' => t('System status')],
 ];