Let plugins run their own PHP code

A plugin can now bring a plugin.php that registers hooks, scheduled tasks, its own tables, public pages and admin screens. Failures stay contained to the plugin; a form on a plugin page can be submitted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/Twig/PluginExtension.php

@@ -5,6 +5,7 @@ namespace App\Twig;
 use App\Content\MediaLibrary;
 use App\Domain\InvalidDocument;
 use App\Plugin\PluginRegistry;
+use App\Plugin\PluginRuntime;
 use Twig\Extension\AbstractExtension;
 use Twig\Loader\FilesystemLoader;
 use Twig\TwigFunction;
@@ -15,7 +16,7 @@ use Twig\TwigFunction;
  */
 final class PluginExtension extends AbstractExtension
 {
-    public function __construct(private PluginRegistry $plugins, private MediaLibrary $media, FilesystemLoader $loader)
+    public function __construct(private PluginRegistry $plugins, private MediaLibrary $media, FilesystemLoader $loader, private PluginRuntime $runtime)
     {
         // Der Namensraum @plugins zeigt auf den Pluginordner - aber nur, wenn es ihn gibt. Ein
         // fester Pfad in twig.yaml liesse eine Installation ohne plugins/ mit einem Ladefehler
@@ -33,6 +34,7 @@ final class PluginExtension extends AbstractExtension
             new TwigFunction('kant_plugin_props', $this->props(...)),
             new TwigFunction('kant_plugin_media', $this->mediaItem(...)),
             new TwigFunction('kant_plugin_settings', $this->plugins->settingsOf(...)),
+            new TwigFunction('kant_plugin_data', $this->runtime->data(...)),
             new TwigFunction('kant_media', $this->adminMedia(...)),
         ];
     }