Tag blog posts and sign them with a member

Tags are named in every language and made from the page form; the byline is
the member who signs a post on the site. The public API sends both, filters
posts by tag and lists the tags in use.

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

lang/ca/panel.php

@@ -63,6 +63,8 @@ return [
             'seo_hint' => 'Metadades per a cercadors i xarxes socials.',
         ],
         'fields' => [
+            'byline' => 'Signatura',
+            'byline_hint' => 'Qui signa l\'entrada al web, amb enllaç al seu perfil. Si es deixa buit no es mostra autoria.',
             'title' => 'Títol',
             'slug' => 'Slug',
             'excerpt' => 'Extracte',
@@ -144,6 +146,16 @@ return [
         'select_all' => 'Selecciona-ho tot',
     ],
 
+    'tags' => [
+        'label' => 'Etiqueta',
+        'plural' => 'Etiquetes',
+        'fields' => [
+            'name' => 'Nom',
+            'slug' => 'Slug',
+            'pages' => 'Entrades',
+        ],
+    ],
+
     'translate' => [
         'title' => 'Traduccions',
         'title_for' => ':title en :language',