feat: expand multiplayer, chat, and release support

- add network NPC synchronization and dialogue interactions
- add world bulletin publishing and display
- improve authentication, session refresh, and appearance sync
- synchronize player direction and movement animations
- improve input focus and progressive Web loading
- add macOS/Windows builds and deployment configuration
- include required fonts, shaders, and runtime assets

_Core/managers/WebSocketManager.gd

@@ -69,7 +69,7 @@ enum ConnectionState {
 # ============================================================================
 
 # WebSocket 服务器 URL（原生 WebSocket）
-const WEBSOCKET_URL: String = "wss://whaletownend.xinghangee.icu/game"
+const WEBSOCKET_URL: String = "wss://whaletown.novamailio.com/game"
 
 # 默认最大重连次数
 const DEFAULT_MAX_RECONNECT_ATTEMPTS: int = 5
@@ -119,6 +119,9 @@ var _heartbeat_timer: Timer
 
 # 心跳间隔（秒）
 const HEARTBEAT_INTERVAL: float = 30.0
+const HEARTBEAT_TIMEOUT: float = 75.0
+
+var _last_server_message_at_msec: int = 0
 
 # ============================================================================
 # 生命周期方法
@@ -149,6 +152,7 @@ func _process(_delta: float) -> void:
 		while _websocket_peer.get_available_packet_count() > 0:
 			var packet: PackedByteArray = _websocket_peer.get_packet()
 			var message: String = packet.get_string_from_utf8()
+			_last_server_message_at_msec = Time.get_ticks_msec()
 
 			# 发射消息接收信号
 			data_received.emit(message)
@@ -194,9 +198,6 @@ func connect_to_game_server(is_reconnect_attempt: bool = false) -> void:
 			_set_connection_state(ConnectionState.ERROR)
 		return
 
-	# 启动心跳
-	_start_heartbeat()
-
 # 断开 WebSocket 连接
 func disconnect_websocket() -> void:
 	_disconnect()
@@ -358,9 +359,12 @@ func _on_websocket_connected() -> void:
 		reconnection_succeeded.emit()
 
 	_set_connection_state(ConnectionState.CONNECTED)
+	_last_server_message_at_msec = Time.get_ticks_msec()
+	_start_heartbeat()
 
 # WebSocket 连接关闭处理
 func _on_websocket_closed() -> void:
+	_stop_heartbeat()
 	if not _manual_disconnect_requested and _auto_reconnect_enabled:
 		connection_lost.emit()
 		_attempt_reconnect()
@@ -382,13 +386,6 @@ func _setup_reconnect_timer() -> void:
 
 # 尝试重连
 func _attempt_reconnect() -> void:
-	# 检查是否超过最大重连次数
-	if _reconnect_attempt >= _max_reconnect_attempts:
-		push_error("WebSocketManager: 达到最大重连次数 (%d)，停止重连" % _max_reconnect_attempts)
-		reconnection_failed.emit(_reconnect_attempt, _max_reconnect_attempts)
-		_set_connection_state(ConnectionState.ERROR)
-		return
-
 	_reconnect_attempt += 1
 	_set_connection_state(ConnectionState.RECONNECTING)
 
@@ -401,7 +398,8 @@ func _attempt_reconnect() -> void:
 # 计算重连延迟（指数退避）
 func _calculate_reconnect_delay() -> float:
 	# 指数退避: base_delay * 2^(attempt-1)
-	var delay: float = _reconnect_base_delay * pow(2.0, _reconnect_attempt - 1)
+	var cappedAttempt := mini(_reconnect_attempt, maxi(_max_reconnect_attempts, 1))
+	var delay: float = _reconnect_base_delay * pow(2.0, cappedAttempt - 1)
 
 	# 限制最大延迟
 	return min(delay, MAX_RECONNECT_DELAY)
@@ -434,9 +432,16 @@ func _stop_heartbeat() -> void:
 
 # 心跳超时处理
 func _on_heartbeat() -> void:
-	# 不发送心跳，避免服务器返回 "消息格式错误"
-	# 如果需要心跳，服务器应该支持特定格式
-	pass
+	if _websocket_peer.get_ready_state() != WebSocketPeer.STATE_OPEN:
+		return
+	var now := Time.get_ticks_msec()
+	if _last_server_message_at_msec > 0 and now - _last_server_message_at_msec > int(HEARTBEAT_TIMEOUT * 1000.0):
+		push_warning("WebSocketManager: 心跳超时，正在重新连接")
+		_websocket_peer.close(4000, "Heartbeat timeout")
+		return
+	var err := _websocket_peer.send_text(JSON.stringify({"type": "ping"}))
+	if err != OK:
+		push_warning("WebSocketManager: 心跳发送失败 - %s" % error_string(err))
 
 # ============================================================================
 # 工具方法
@@ -455,7 +460,7 @@ func get_state_description() -> String:
 		ConnectionState.CONNECTED:
 			return "已连接"
 		ConnectionState.RECONNECTING:
-			return "重连中 (%d/%d)" % [_reconnect_attempt, _max_reconnect_attempts]
+			return "重连中 (第 %d 次)" % _reconnect_attempt
 		ConnectionState.ERROR:
 			return "错误"
 		_: