fix: update visionData cache immediately before network save

Prevents stale reads when renderMoodboard runs after saveVisionSection

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

public/index.html

@@ -1013,13 +1013,12 @@ function showSaved() {
 async function saveVisionSection(section, contenu) {
   const row = visionData[section];
   if (!row) return;
-  await fetch(`/api/vision/${row.Id}`, {
+  row.Contenu = contenu; // update local cache immediately
+  fetch(`/api/vision/${row.Id}`, {
     method: 'PATCH',
     headers: { 'Content-Type': 'application/json' },
     body: JSON.stringify({ Contenu: contenu }),
-  });
-  row.Contenu = contenu;
-  showSaved();
+  }).then(() => showSaved());
 }
 
 function setupEditable(elId, section) {