Add chat widget improvements and chat history component

Widget improvements:
- Pulsating badge with unread message count on floating button
- Clickable ticket reference link in chat header
- ExternalLink icon on hover

Desktop (Raven) improvements:
- Track previous unread count for new message detection
- Send native Windows notifications for new messages
- Focus chat window when new messages arrive

Chat history:
- New query getTicketChatHistory for fetching chat sessions and messages
- New component TicketChatHistory displaying chat sessions
- Sessions can be expanded/collapsed to view messages
- Pagination support for long conversations
- Added to both dashboard and portal ticket views

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

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

apps/desktop/src-tauri/src/chat.rs

@@ -267,6 +267,7 @@ impl ChatPollerHandle {
 pub struct ChatRuntime {
     inner: Arc<Mutex<Option<ChatPollerHandle>>>,
     last_sessions: Arc<Mutex<Vec<ChatSession>>>,
+    last_unread_count: Arc<Mutex<u32>>,
 }
 
 impl ChatRuntime {
@@ -274,6 +275,7 @@ impl ChatRuntime {
         Self {
             inner: Arc::new(Mutex::new(None)),
             last_sessions: Arc::new(Mutex::new(Vec::new())),
+            last_unread_count: Arc::new(Mutex::new(0)),
         }
     }
 
@@ -301,6 +303,7 @@ impl ChatRuntime {
         let base_clone = sanitized_base.clone();
         let token_clone = token.clone();
         let last_sessions = self.last_sessions.clone();
+        let last_unread_count = self.last_unread_count.clone();
 
         let join_handle = tauri::async_runtime::spawn(async move {
             crate::log_info!("Chat polling iniciado");
@@ -379,10 +382,15 @@ impl ChatRuntime {
                                     }
 
                                     // Verificar mensagens nao lidas e emitir evento
+                                    let prev_unread = *last_unread_count.lock();
+                                    let new_messages = result.total_unread > prev_unread;
+                                    *last_unread_count.lock() = result.total_unread;
+
                                     if result.total_unread > 0 {
                                         crate::log_info!(
-                                            "Chat: {} mensagens nao lidas",
-                                            result.total_unread
+                                            "Chat: {} mensagens nao lidas (prev={})",
+                                            result.total_unread,
+                                            prev_unread
                                         );
                                         let _ = app.emit(
                                             "raven://chat/unread-update",
@@ -391,6 +399,37 @@ impl ChatRuntime {
                                                 "sessions": result.sessions
                                             }),
                                         );
+
+                                        // Notificar novas mensagens (apenas se aumentou)
+                                        if new_messages && prev_unread > 0 {
+                                            let new_count = result.total_unread - prev_unread;
+                                            let notification_title = "Nova mensagem de suporte";
+                                            let notification_body = if new_count == 1 {
+                                                "Voce recebeu 1 nova mensagem no chat".to_string()
+                                            } else {
+                                                format!("Voce recebeu {} novas mensagens no chat", new_count)
+                                            };
+                                            if let Err(e) = app
+                                                .notification()
+                                                .builder()
+                                                .title(notification_title)
+                                                .body(&notification_body)
+                                                .show()
+                                            {
+                                                crate::log_warn!(
+                                                    "Falha ao enviar notificacao de nova mensagem: {e}"
+                                                );
+                                            }
+
+                                            // Focar janela de chat se existir
+                                            if let Some(session) = result.sessions.first() {
+                                                let label = format!("chat-{}", session.ticket_id);
+                                                if let Some(window) = app.get_webview_window(&label) {
+                                                    let _ = window.show();
+                                                    let _ = window.set_focus();
+                                                }
+                                            }
+                                        }
                                     }
                                 } else {
                                     // Sem sessoes ativas