refactor: enhance markdown processing and code structure

- Updated the ConduitMarkdown class to streamline markdown rendering, improving maintainability and clarity.
- Refactored the markdown configuration to utilize new methods for building markdown blocks and handling LaTeX syntax.
- Improved the StreamingMarkdownWidget to leverage the updated markdown processing logic, ensuring a cohesive user experience.
- Enhanced the handling of Mermaid diagrams and LaTeX rendering, providing better support for complex markdown content.

lib/core/auth/auth_state_manager.dart

@@ -610,12 +610,11 @@ class AuthStateManager extends _$AuthStateManager {
 
   /// Prime the conversations list so navigation drawers show real data after login.
   void _prefetchConversations() {
-    Future.microtask(() async {
+    Future.microtask(() {
       if (!ref.mounted) return;
       try {
         refreshConversationsCache(ref, includeFolders: true);
-        await ref.read(conversationsProvider.future);
-        DebugLogger.auth('Conversations prefetch requested');
+        DebugLogger.auth('Conversations prefetch scheduled');
       } catch (e) {
         if (!ref.mounted) return;
         DebugLogger.warning(