v2.6.1d (Lyra): Plugin i18n, plugin editor vernieuwd, media invoegen

Plugin internationalisatie: plugins hebben eigen language/ mappen. Systeem
plugins volgen admin taal (admin.php), content plugins volgen content taal
(site.php). Fallback chain: geselecteerd -> plugin default_language -> CMS
default. PluginManager/AdminPluginAPI/CMSAPI uitgebreid met
getPluginTranslations()/t(). plugin.json settings ondersteunen
label_key/help_key/option_label_key.

Plugin uniformiteit: alle 6 plugins hebben uniforme structuur (README.md,
assets/.gitkeep, language/nl|en/). plugins/README.md herschreven.
guide plugin-development.md (NL+EN) volledig herschreven.

Plugin editor vernieuwd: geneste bestandsbrowser zijbalk, nieuw bestand
aanmaken, uploaden naar assets/, verwijderen en verplaatsen. Nieuwe routes:
plugins-file-upload, plugins-file-delete, plugins-file-move. Path-traversal
bescherming + protected plugins geblokkeerd.

Media invoegen in editor: nieuw /admin/media-list JSON endpoint + herbruikbare
_media-modal.twig include. Plugin-context scant assets/ map. editor-toolbar.js
modeMap uitgebreid voor css/scss/js/json.

Plugin overzicht knoppen: alleen iconen met title/aria-label.

Tests: pentest 30/30, WCAG 2.1 AA 25/25.

plugins/Statistics/language/en/admin.php

@@ -0,0 +1,32 @@
+<?php
+return [
+    // Menu
+    'menu_label' => 'Statistics',
+
+    // Page
+    'page_title' => 'Statistics',
+    'total_views' => 'Total views',
+    'unique_visitors' => 'Unique visitors',
+    'page_views' => 'Page views',
+    'countries' => 'Countries',
+    'top_pages' => 'Top pages',
+    'no_data' => 'No data',
+    'col_country' => 'Country',
+    'col_views' => 'Views',
+    'col_page' => 'Page',
+    'analytics_disabled' => 'Analytics is disabled.',
+
+    // Settings (plugin.json label_key/help_key)
+    'setting_required_roles' => 'Roles allowed to view this plugin',
+    'setting_required_roles_help' => 'Determines which roles can access the statistics page in the admin panel. Admin always has access.',
+    'role_options' => [
+        'admin' => 'Admin',
+        'content-manager' => 'Content Manager',
+        'bi-manager' => 'BI Manager',
+        'site-admin' => 'Site Admin',
+    ],
+    'setting_show_countries' => 'Show countries overview',
+    'setting_show_countries_help' => 'Enable or disable the countries overview on the statistics page.',
+    'setting_show_top_pages' => 'Show top pages',
+    'setting_show_top_pages_help' => 'Enable or disable the top pages overview.',
+];