Add plugin system and improve language handling

Add global and page-level plugin support Implement language-aware
content filtering Add month translations to language files Refactor date
formatting to use translations Move translation loading to plugin system
Improve content availability checks

app/config.php

@@ -7,6 +7,9 @@ function createContext(): Context {
         : __DIR__ . '/config.ini';
     $config = parse_ini_file($configFile, true);
 
+    // Load global plugins
+    getPluginManager()->loadGlobalPlugins($config);
+
     $defaultLang = $config['languages']['default'] ?? 'no';
     $availableLangs = array_map('trim', explode(',', $config['languages']['available'] ?? 'no'));