feat(desktop): adiciona hub de chats para multiplas sessoes

- Cria ChatSessionList, ChatSessionItem e ChatHubWidget no desktop
- Adiciona comandos Rust para gerenciar hub window
- Quando ha multiplas sessoes, abre hub ao inves de janela individual
- Hub lista todas as sessoes ativas com badge de nao lidos
- Clicar em sessao abre/foca janela de chat especifica
- Menu do tray abre hub quando ha multiplas sessoes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/desktop/src/chat/ChatSessionItem.tsx

@@ -0,0 +1,82 @@
+import { MessageCircle } from "lucide-react"
+import type { ChatSession } from "./types"
+
+type ChatSessionItemProps = {
+  session: ChatSession
+  isActive?: boolean
+  onClick: () => void
+}
+
+function formatTime(timestamp: number) {
+  const now = Date.now()
+  const diff = now - timestamp
+  const minutes = Math.floor(diff / 60000)
+  const hours = Math.floor(diff / 3600000)
+  const days = Math.floor(diff / 86400000)
+
+  if (minutes < 1) return "Agora"
+  if (minutes < 60) return `${minutes}min`
+  if (hours < 24) return `${hours}h`
+  if (days === 1) return "Ontem"
+
+  return new Date(timestamp).toLocaleDateString("pt-BR", {
+    day: "2-digit",
+    month: "2-digit",
+  })
+}
+
+export function ChatSessionItem({ session, isActive, onClick }: ChatSessionItemProps) {
+  const hasUnread = session.unreadCount > 0
+
+  return (
+    <button
+      type="button"
+      onClick={onClick}
+      className={`flex w-full items-start gap-3 border-b border-slate-100 px-4 py-3 text-left transition-colors hover:bg-slate-50 ${
+        isActive ? "bg-slate-100" : ""
+      } ${hasUnread ? "bg-red-50/50 hover:bg-red-50" : ""}`}
+    >
+      {/* Avatar/Icone */}
+      <div
+        className={`flex size-10 shrink-0 items-center justify-center rounded-full ${
+          hasUnread ? "bg-red-100 text-red-600" : "bg-slate-100 text-slate-600"
+        }`}
+      >
+        <MessageCircle className="size-5" />
+      </div>
+
+      {/* Conteudo */}
+      <div className="min-w-0 flex-1">
+        <div className="flex items-center justify-between gap-2">
+          <div className="flex items-center gap-2">
+            <span className={`text-sm font-semibold ${hasUnread ? "text-red-700" : "text-slate-900"}`}>
+              #{session.ticketRef}
+            </span>
+            {/* Indicador online - sessao ativa significa online */}
+            <span className="size-2 rounded-full bg-emerald-500" title="Online" />
+          </div>
+          <span className="text-xs text-slate-400">
+            {formatTime(session.lastActivityAt)}
+          </span>
+        </div>
+
+        <p className="mt-0.5 truncate text-sm text-slate-600">
+          {session.ticketSubject}
+        </p>
+
+        <p className="mt-0.5 truncate text-xs text-slate-400">
+          {session.agentName}
+        </p>
+      </div>
+
+      {/* Badge de nao lidos */}
+      {hasUnread && (
+        <div className="flex shrink-0 items-center justify-center">
+          <span className="flex size-5 items-center justify-center rounded-full bg-red-500 text-xs font-bold text-white">
+            {session.unreadCount > 9 ? "9+" : session.unreadCount}
+          </span>
+        </div>
+      )}
+    </button>
+  )
+}