feat: téléchargement dans sous-dossiers par catégorie

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

static/app.js

@@ -110,9 +110,10 @@ function renderConcerts(data) {
     const dl  = state.downloadedUrls.has(c.url) ? `<span class="card-downloaded">✓ Téléchargé</span>` : '';
     const date = fmtDate(c.upload_date);
     const sub  = c.subtitle ? `<div class="card-subtitle">${c.subtitle}</div>` : '';
+    const downloadedClass = state.downloadedUrls.has(c.url) ? 'downloaded' : '';
 
     return `
-      <div class="card" data-id="${c.id}" tabindex="0" role="button" aria-label="${c.title}">
+      <div class="card ${downloadedClass}" data-id="${c.id}" tabindex="0" role="button" aria-label="${c.title}">
         <div class="card-thumb-wrap">
           ${thumb}${dur}${dl}
         </div>
@@ -270,7 +271,7 @@ $('btn-download').addEventListener('click', async () => {
     const res = await fetch('/api/download', {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ url: c.url, title: c.title, subtitle: c.subtitle || '', year }),
+      body: JSON.stringify({ url: c.url, title: c.title, subtitle: c.subtitle || '', year, category: state.category }),
     });
     const { id } = await res.json();
     trackDownload(id, c.title, c.url);