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/index.tsx

@@ -1,21 +1,22 @@
 import { ChatWidget } from "./ChatWidget"
+import { ChatHubWidget } from "./ChatHubWidget"
 
 export function ChatApp() {
   // Obter ticketId e ticketRef da URL
   const params = new URLSearchParams(window.location.search)
   const ticketId = params.get("ticketId")
   const ticketRef = params.get("ticketRef")
+  const isHub = params.get("hub") === "true"
 
-  if (!ticketId) {
-    return (
-      <div className="flex h-screen flex-col items-center justify-center bg-white p-4">
-        <p className="text-sm text-red-600">Erro: ticketId não fornecido</p>
-      </div>
-    )
+  // Modo hub - lista de todas as sessoes
+  if (isHub || !ticketId) {
+    return <ChatHubWidget />
   }
 
+  // Modo chat - conversa de um ticket especifico
   return <ChatWidget ticketId={ticketId} ticketRef={ticketRef ? Number(ticketRef) : undefined} />
 }
 
 export { ChatWidget }
+export { ChatHubWidget }
 export * from "./types"