fix: autocomplete fallback markdown + error catch

frontend/editor-poc.html

@@ -1743,13 +1743,18 @@ body { font-family: var(--sans); background: var(--bg); color: var(--text); heig
           m.searchWikilinks(result.partial || '', function(items) {
             showAutocomplete(items, 'Wikilinks');
           });
-        } else if (result.items.length > 0) {
+        } else if (result.items && result.items.length > 0) {
           var ctxLabels = {
             mermaid: 'Mermaid', code: 'Code', fence_open: 'Langage',
             frontmatter: 'Frontmatter', markdown: 'Markdown'
           };
           showAutocomplete(result.items, ctxLabels[result.context] || result.context);
+        } else {
+          // Fallback: show markdown formatting suggestions
+          showAutocomplete(m.MARKDOWN_FORMAT, 'Markdown');
         }
+      }).catch(function(err) {
+        console.error('[Autocomplete] Failed to load module:', err);
       });
     };
     loadAndTrigger();