Feat: page À propos — redesign complet avec carrousel équipe

- Fix about.json.php : lecture des vrais champs Kirby (intro writer,
  body blocks, files template member) — corrige le bug [object Object]
- About.svelte : redesign fidèle à la source (intro centrée, blocs
  mission/manifeste avec bordure verte, carrousel équipe horizontal
  3/2/1 items selon breakpoint, swipe tactile, prev/next + pagination)

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

site/templates/about.json.php

@@ -1,31 +1,25 @@
 <?php
 
+$bodyBlocks = [];
+foreach ($page->body()->toBlocks() as $block) {
+    if ($block->type() === 'text') {
+        $bodyBlocks[] = [
+            'type' => 'text',
+            'html' => $block->content()->text()->value()
+        ];
+    }
+}
+
 $specificData = [
-  'intro' => [
-    'title' => $page->introTitle()->value(),
-    'text' => $page->introText()->value()
-  ],
-  'mission' => [
-    'title' => $page->missionTitle()->value(),
-    'text' => $page->missionText()->toBlocks()
-  ],
-  'manifesto' => [
-    'title' => $page->manifestoTitle()->value(),
-    'text' => $page->manifestoText()->toBlocks()
-  ],
-  'team' => [
-    'title' => $page->teamTitle()->value(),
-    'members' => $page->teamMembers()->toStructure()->map(function($member) {
-      return [
-        'name' => $member->name()->value(),
-        'role' => $member->role()->value(),
-        'bio' => $member->bio()->value(),
-        'photo' => $member->photo()->toFile()?->url(),
-        'linkedin' => $member->linkedin()->value(),
-        'twitter' => $member->twitter()->value()
-      ];
+    'intro' => $page->intro()->value(),
+    'body'  => $bodyBlocks,
+    'team'  => $page->files()->template('member')->sort('sort')->map(function ($file) {
+        return [
+            'name'  => $file->memberName()->value(),
+            'role'  => $file->role()->value(),
+            'photo' => $file->url(),
+        ];
     })->values()
-  ]
 ];
 
 $pageData = array_merge($genericData, $specificData);