feat: integrate Better Auth and enhance authentication flow

- Added Better Auth integration to the web application, allowing for dual login support with both custom and Better Auth systems.
- Updated authentication client configuration to dynamically set the base URL based on the environment.
- Enhanced chat components to utilize user authentication status, improving user experience and security.
- Refactored various components to support Better Auth, including error handling and user identity management.
- Improved notification handling and user feedback mechanisms during authentication processes.

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

@@ -2,8 +2,11 @@
   import { useConvexClient } from "convex-svelte";
   import { api } from "@sgse-app/backend/convex/_generated/api";
   import { onMount } from "svelte";
+  import { authStore } from "$lib/stores/auth.svelte";
 
   const client = useConvexClient();
+  
+  // Token é passado automaticamente via interceptadores em +layout.svelte
 
   let heartbeatInterval: ReturnType<typeof setInterval> | null = null;
   let inactivityTimeout: ReturnType<typeof setTimeout> | null = null;