refactor: move coverFiles to plugin as page/file methods

Replace GeoformatPage model with a plugin registering coverFiles as a
pageMethod (available on all pages) and coverLabel as a fileMethod to
display "Carte [title]" for map children files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/site/blueprints/pages/geoformat.yml

@@ -22,6 +22,7 @@ tabs:
                 label: Media de couverture
                 type: files
                 query: page.coverFiles
+                text: "{{ file.coverLabel }}"
                 multiple: false
                 width: 1/2
               text:

public/site/blueprints/pages/narrative.yml

@@ -18,6 +18,8 @@ tabs:
               cover:
                 label: Image de couverture
                 type: files
+                query: page.coverFiles
+                text: "{{ file.coverLabel }}"
                 multiple: false
                 width: 1/2
               introduction:

public/site/models/geoformat.php

@@ -1,13 +0,0 @@
-<?php
-
-use Kirby\Cms\Page;
-
-class GeoformatPage extends Page
-{
-    public function coverFiles()
-    {
-        return $this->files()->add(
-            $this->children()->filterBy('intendedTemplate', 'map')->files()
-        );
-    }
-}

public/site/plugins/cover-files/index.php

@@ -0,0 +1,19 @@
+<?php
+
+Kirby::plugin('geoproject/cover-files', [
+    'pageMethods' => [
+        'coverFiles' => function () {
+            return $this->files()->add(
+                $this->children()->filterBy('intendedTemplate', 'map')->files()
+            );
+        }
+    ],
+    'fileMethods' => [
+        'coverLabel' => function () {
+            if ($this->parent()->intendedTemplate()->name() === 'map') {
+                return 'Carte ' . $this->parent()->title();
+            }
+            return $this->filename();
+        }
+    ]
+]);