feat(chat): add conversation selection and enhance message rendering

- Add currentConversationId prop to ChatContainer for loading selected conversations
- Implement logic to load messages when conversation is selected and clear when deselected
- Improve user message rendering with proper whitespace handling
- Enhance MarkdownRenderer with content normalization and adjusted spacing for better readability
- Add paragraph styling to markdown output for improved layout

This enables users to switch between conversations seamlessly and provides cleaner message display.

components/ClientHome.tsx

@@ -62,6 +62,7 @@ export function ClientHome({ offline, models }: ClientHomeProps) {
             models={models}
             offline={offline}
             onConversationCreated={handleConversationCreated}
+            currentConversationId={currentConversationId}
           />
         </div>
       </main>