fix: Show RAG context sidebar when chunks are received

The sidebar content was hidden by default (display: none) but
displayContext() never made it visible when chunks arrived.
Added sidebarContent.style.display = 'block' to show the
context panel with all RAG chunks.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

generations/library_rag/templates/chat.html

@@ -1608,9 +1608,13 @@
 
         if (!chunks || chunks.length === 0) {
             sidebarContent.innerHTML = '<div class="sidebar-empty">Aucun contexte trouvé</div>';
+            sidebarContent.style.display = 'block';
             return;
         }
 
+        // Show sidebar when we have chunks
+        sidebarContent.style.display = 'block';
+
         chunks.forEach((chunk, index) => {
             const chunkDiv = document.createElement('div');
             chunkDiv.className = 'context-chunk';