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/chat/PresenceManager.svelte

@@ -0,0 +1,87 @@
+<script lang="ts">
+  import { useConvexClient } from "convex-svelte";
+  import { api } from "@sgse-app/backend/convex/_generated/api";
+  import { onMount } from "svelte";
+
+  const client = useConvexClient();
+
+  let heartbeatInterval: ReturnType<typeof setInterval> | null = null;
+  let inactivityTimeout: ReturnType<typeof setTimeout> | null = null;
+  let lastActivity = Date.now();
+
+  // Detectar atividade do usuário
+  function handleActivity() {
+    lastActivity = Date.now();
+    
+    // Limpar timeout de inatividade anterior
+    if (inactivityTimeout) {
+      clearTimeout(inactivityTimeout);
+    }
+
+    // Configurar novo timeout (5 minutos)
+    inactivityTimeout = setTimeout(() => {
+      client.mutation(api.chat.atualizarStatusPresenca, { status: "ausente" });
+    }, 5 * 60 * 1000);
+  }
+
+  onMount(() => {
+    // Configurar como online ao montar
+    client.mutation(api.chat.atualizarStatusPresenca, { status: "online" });
+
+    // Heartbeat a cada 30 segundos
+    heartbeatInterval = setInterval(() => {
+      const timeSinceLastActivity = Date.now() - lastActivity;
+      
+      // Se houve atividade nos últimos 5 minutos, manter online
+      if (timeSinceLastActivity < 5 * 60 * 1000) {
+        client.mutation(api.chat.atualizarStatusPresenca, { status: "online" });
+      }
+    }, 30 * 1000);
+
+    // Listeners para detectar atividade
+    const events = ["mousedown", "keydown", "scroll", "touchstart"];
+    events.forEach((event) => {
+      window.addEventListener(event, handleActivity);
+    });
+
+    // Configurar timeout inicial de inatividade
+    handleActivity();
+
+    // Detectar quando a aba fica inativa/ativa
+    function handleVisibilityChange() {
+      if (document.hidden) {
+        // Aba ficou inativa
+        client.mutation(api.chat.atualizarStatusPresenca, { status: "ausente" });
+      } else {
+        // Aba ficou ativa
+        client.mutation(api.chat.atualizarStatusPresenca, { status: "online" });
+        handleActivity();
+      }
+    }
+
+    document.addEventListener("visibilitychange", handleVisibilityChange);
+
+    // Cleanup
+    return () => {
+      // Marcar como offline ao desmontar
+      client.mutation(api.chat.atualizarStatusPresenca, { status: "offline" });
+
+      if (heartbeatInterval) {
+        clearInterval(heartbeatInterval);
+      }
+
+      if (inactivityTimeout) {
+        clearTimeout(inactivityTimeout);
+      }
+
+      events.forEach((event) => {
+        window.removeEventListener(event, handleActivity);
+      });
+
+      document.removeEventListener("visibilitychange", handleVisibilityChange);
+    };
+  });
+</script>
+
+<!-- Componente invisível - apenas lógica -->
+