refactor: harden client runtime and exports

_Core/chat/ChatMessageCodec.gd

@@ -0,0 +1,54 @@
+extends RefCounted
+
+# 统一转换后端聊天载荷，避免 WebSocket 实时消息和 HTTP 历史消息
+# 各自维护一套时间戳兼容规则。
+
+static func normalize_history(messages: Array, current_username: String) -> Array[Dictionary]:
+	var normalized: Array[Dictionary] = []
+	for message_variant: Variant in messages:
+		if not (message_variant is Dictionary):
+			continue
+		var message: Dictionary = message_variant
+		var sender := str(message.get("sender", message.get("from_user", "")))
+		normalized.append({
+			"from_user": sender,
+			"from_user_id": str(message.get("fromUserId", message.get("from_user_id", ""))),
+			"content": str(message.get("content", "")),
+			"timestamp": parse_timestamp(message.get("timestamp", 0.0)),
+			"is_self": sender == current_username,
+			"scope": str(message.get("scope", "local")),
+			"show_bubble": bool(message.get("bubble", false)),
+			"is_history": true,
+		})
+	return normalized
+
+static func parse_timestamp(timestamp_raw: Variant) -> float:
+	if typeof(timestamp_raw) == TYPE_INT or typeof(timestamp_raw) == TYPE_FLOAT:
+		var numeric_timestamp := float(timestamp_raw)
+		return numeric_timestamp if numeric_timestamp > 0.0 else Time.get_unix_time_from_system()
+
+	var timestamp_text := str(timestamp_raw)
+	if timestamp_text.strip_edges().is_empty():
+		return Time.get_unix_time_from_system()
+
+	var numeric_regex := RegEx.new()
+	numeric_regex.compile("^\\s*-?\\d+(?:\\.\\d+)?\\s*$")
+	if numeric_regex.search(timestamp_text) != null:
+		var parsed_numeric := float(timestamp_text)
+		return parsed_numeric if parsed_numeric > 0.0 else Time.get_unix_time_from_system()
+
+	var iso_regex := RegEx.new()
+	iso_regex.compile("(\\d{4})-(\\d{2})-(\\d{2})T(\\d{2}):(\\d{2}):(\\d{2})")
+	var match_result := iso_regex.search(timestamp_text)
+	if match_result == null:
+		return Time.get_unix_time_from_system()
+
+	var utc_datetime := {
+		"year": int(match_result.get_string(1)),
+		"month": int(match_result.get_string(2)),
+		"day": int(match_result.get_string(3)),
+		"hour": int(match_result.get_string(4)),
+		"minute": int(match_result.get_string(5)),
+		"second": int(match_result.get_string(6)),
+	}
+	return Time.get_unix_time_from_datetime_dict(utc_datetime)