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.

scripts/init-db.ts

@@ -131,7 +131,7 @@ export async function initializeEmbeddingModel(): Promise<void> {
   try {
     await ensureModelExists(
       "nomic-embed-text",
-      "Este modelo será usado para busca vetorial das mensagens"
+      "Este modelo será usado para busca vetorial das mensagens (274MB - 768 dimensões)"
     );
     console.log("✅ Modelo de embedding pronto!");
   } catch (error) {