refactor: modify markdown append message content structure to use array format

Change the message content from a plain string to an array of objects with type and text fields to support future extensibility of message formats

Author: xKevIsDev

app/components/chat/Markdown.tsx

@@ -110,15 +110,25 @@ export const Markdown = memo(
                   } else if (type === 'message' && append) {
                     append({
                       id: `quick-action-message-${Date.now()}`,
-                      content: `[Model: ${model}]\n\n[Provider: ${provider?.name}]\n\n${message}`,
+                      content: [
+                        {
+                          type: 'text',
+                          text: `[Model: ${model}]\n\n[Provider: ${provider?.name}]\n\n${message}`,
+                        },
+                      ] as any,
                       role: 'user',
                     });
                     console.log('Message appended:', message);
                   } else if (type === 'implement' && append && setChatMode) {
                     setChatMode('build');
                     append({
                       id: `quick-action-implement-${Date.now()}`,
-                      content: `[Model: ${model}]\n\n[Provider: ${provider?.name}]\n\n${message}`,
+                      content: [
+                        {
+                          type: 'text',
+                          text: `[Model: ${model}]\n\n[Provider: ${provider?.name}]\n\n${message}`,
+                        },
+                      ] as any,
                       role: 'user',
                     });
                   } else if (type === 'link' && typeof href === 'string') {