feat: enhance ErrorModal and chat components with new features and improvements

- Refactored ErrorModal to utilize a dialog element for better accessibility and user experience, including a close button with an icon.
- Updated chat components to improve participant display and message read status, enhancing user engagement and clarity.
- Introduced loading indicators for user and conversation data in SalaReuniaoManager to improve responsiveness during data fetching.
- Enhanced message handling in MessageList to indicate whether messages have been read, providing users with better feedback on message status.
- Improved overall structure and styling across various components for consistency and maintainability.

apps/web/src/lib/components/chat/ScheduleMessageModal.svelte

@@ -4,6 +4,7 @@
   import type { Id } from "@sgse-app/backend/convex/_generated/dataModel";
   import { format } from "date-fns";
   import { ptBR } from "date-fns/locale";
+  import { Clock, X, Trash2 } from "lucide-svelte";
 
   interface Props {
     conversaId: Id<"conversas">;