feat: implement comprehensive chat system with user presence management, notification handling, and avatar integration; enhance UI components for improved user experience

apps/web/src/lib/components/Sidebar.svelte

@@ -7,6 +7,9 @@
   import { loginModalStore } from "$lib/stores/loginModal.svelte";
   import { useConvexClient } from "convex-svelte";
   import { api } from "@sgse-app/backend/convex/_generated/api";
+  import NotificationBell from "$lib/components/chat/NotificationBell.svelte";
+  import ChatWidget from "$lib/components/chat/ChatWidget.svelte";
+  import PresenceManager from "$lib/components/chat/PresenceManager.svelte";
 
   let { children }: { children: Snippet } = $props();
 
@@ -174,6 +177,9 @@
   </div>
   <div class="flex-none flex items-center gap-4">
     {#if authStore.autenticado}
+      <!-- Sino de notificações -->
+      <NotificationBell />
+      
       <div class="hidden lg:flex flex-col items-end">
         <span class="text-sm font-semibold text-primary">{authStore.usuario?.nome}</span>
         <span class="text-xs text-base-content/60">{authStore.usuario?.role.nome}</span>
@@ -529,3 +535,9 @@
   </dialog>
 {/if}
 
+<!-- Componentes de Chat (apenas se autenticado) -->
+{#if authStore.autenticado}
+  <PresenceManager />
+  <ChatWidget />
+{/if}
+