feat: ajouté support markdown dans export PDF

- Parser markdown avec marked pour rendu HTML complet
- Styles CSS pour éléments markdown (headings, listes, code, etc.)
- Nettoyage automatique des styles temporaires
- Fallback texte brut si parsing markdown échoue

components/versions/export-pdf-button.js

@@ -7,6 +7,45 @@ import CircularProgress from '@mui/material/CircularProgress'
 import PictureAsPdfIcon from '@mui/icons-material/PictureAsPdf'
 import {formatDate} from '@/lib/format.js'
 
+// Helper function to render markdown to HTML
+const renderMarkdownToHtml = async content => {
+  if (!content) {
+    return 'Aucun contenu disponible'
+  }
+
+  // Check if content contains markdown syntax
+  const hasMarkdown = content.includes('**')
+    || content.includes('*')
+    || content.includes('#')
+    || content.includes('[')
+    || content.includes('`')
+    || content.includes('> ')
+    || content.includes('- ')
+    || content.includes('1. ')
+
+  if (!hasMarkdown) {
+    // Simple text with line breaks
+    return content.replaceAll('\n', '<br>')
+  }
+
+  try {
+    // Dynamic import of markdown parser
+    const {marked} = await import('marked')
+    // Configure marked for better PDF rendering
+    marked.setOptions({
+      breaks: true, // Convert \n to <br>
+      gfm: true, // GitHub flavored markdown
+      headerIds: false, // No header IDs needed for PDF
+      mangle: false // Don't mangle email addresses
+    })
+
+    return marked(content)
+  } catch (error) {
+    console.warn('Failed to parse markdown, falling back to plain text:', error)
+    return content.replaceAll('\n', '<br>')
+  }
+}
+
 export default function ExportPdfButton({versionData, size = 'medium', variant = 'outlined'}) {
   const [isExporting, setIsExporting] = useState(false)
 
@@ -32,12 +71,83 @@ export default function ExportPdfButton({versionData, size = 'medium', variant =
         z-index: -1;
       `
 
+      // Add CSS styles for markdown elements
+      const styleElement = document.createElement('style')
+      styleElement.textContent = `
+        .pdf-content h1, .pdf-content h2, .pdf-content h3, .pdf-content h4, .pdf-content h5, .pdf-content h6 {
+          margin: 20px 0 10px 0;
+          font-weight: bold;
+          color: #333;
+        }
+        .pdf-content h1 { font-size: 24px; color: #1976d2; }
+        .pdf-content h2 { font-size: 20px; }
+        .pdf-content h3 { font-size: 18px; }
+        .pdf-content h4 { font-size: 16px; }
+        .pdf-content p { margin: 10px 0; }
+        .pdf-content strong, .pdf-content b { font-weight: bold; }
+        .pdf-content em, .pdf-content i { font-style: italic; }
+        .pdf-content ul, .pdf-content ol { 
+          margin: 10px 0; 
+          padding-left: 25px; 
+        }
+        .pdf-content li { margin: 5px 0; }
+        .pdf-content blockquote { 
+          margin: 15px 0; 
+          padding: 10px 20px; 
+          border-left: 4px solid #1976d2; 
+          background-color: #f5f5f5; 
+          font-style: italic; 
+        }
+        .pdf-content code { 
+          background-color: #f5f5f5; 
+          padding: 2px 4px; 
+          border-radius: 3px; 
+          font-family: 'Courier New', monospace; 
+          font-size: 13px; 
+        }
+        .pdf-content pre { 
+          background-color: #f5f5f5; 
+          padding: 15px; 
+          border-radius: 5px; 
+          overflow-x: auto; 
+          margin: 15px 0; 
+        }
+        .pdf-content pre code { 
+          background: none; 
+          padding: 0; 
+        }
+        .pdf-content a { color: #1976d2; text-decoration: underline; }
+        .pdf-content hr { 
+          border: none; 
+          border-top: 1px solid #ccc; 
+          margin: 20px 0; 
+        }
+        .pdf-content table { 
+          border-collapse: collapse; 
+          margin: 15px 0; 
+          width: 100%; 
+        }
+        .pdf-content th, .pdf-content td { 
+          border: 1px solid #ccc; 
+          padding: 8px; 
+          text-align: left; 
+        }
+        .pdf-content th { 
+          background-color: #f5f5f5; 
+          font-weight: bold; 
+        }
+      `
+      document.head.append(styleElement)
+
       const authorName = versionData.user_created?.split('-')[0] || 'Système'
       const createdAt = new Date(versionData.date_created)
       const threeDaysAgo = new Date(Date.now() - (3 * 24 * 60 * 60 * 1000))
       const voteStatus = createdAt < threeDaysAgo ? 'fermé' : 'ouvert'
       const voteColor = voteStatus === 'ouvert' ? '#2e7d32' : '#d32f2f'
 
+      // Render markdown content to HTML
+      const renderedContent = await renderMarkdownToHtml(versionData.delta?.contenu)
+
       tempDiv.innerHTML = `
         <div style="margin-bottom: 30px; border-bottom: 2px solid #1976d2; padding-bottom: 20px;">
           <h1 style="color: #1976d2; margin: 0 0 10px 0; font-size: 28px; font-weight: bold;">
@@ -61,8 +171,8 @@ export default function ExportPdfButton({versionData, size = 'medium', variant =
           <h2 style="color: #333; font-size: 20px; margin-bottom: 15px; font-weight: bold;">
             Contenu
           </h2>
-          <div style="white-space: pre-wrap; font-size: 14px; line-height: 1.8; text-align: justify;">
-            ${versionData.delta?.contenu || 'Aucun contenu disponible'}
+          <div class="pdf-content" style="font-size: 14px; line-height: 1.8; text-align: justify;">
+            ${renderedContent}
           </div>
         </div>
         
@@ -84,6 +194,7 @@ export default function ExportPdfButton({versionData, size = 'medium', variant =
       })
 
       tempDiv.remove()
+      styleElement.remove() // Clean up styles
 
       // Créer le PDF
       const imgData = canvas.toDataURL('image/png', 1)