refactor(agui): replace addition mode enum with merge options for flexible event merging

This change replaces the AdditionMode enum with MergeOptions for more flexible control over how addition fields are merged with event data. The StreamStateMachine class is introduced to handle streaming state management, improving tool call handling and UUID resolution in copilotkit compatibility mode. The protocol handlers are updated to use the new merge options instead of the rigid enum-based approach.

This provides better flexibility for merging additional fields while maintaining backward compatibility through the merge helper function.

feat: 使用 MergeOptions 替换 AdditionMode 枚举以实现灵活的事件合并

此变更使用 MergeOptions 替换 AdditionMode 枚举，以实现对附加字段如何与事件数据合并的更灵活控制。引入了 StreamStateMachine 类来处理流状态管理，改进了在 copilotkit 兼容模式下的工具调用处理和 UUID 解析。协议处理器已更新以使用新的合并选项，而不是基于枚举的刚性方法。

这为合并附加字段提供了更好的灵活性，同时通过合并助手函数保持向后兼容性。

Change-Id: Ic84a5a9b743e7bedbc75e5938248b34348f17591
Signed-off-by: OhYee <oyohyee@oyohyee.com>

Author: OhYee

agentrun/integration/langgraph/agent_converter.py

@@ -210,8 +210,8 @@ def _filter_tool_input(tool_input: Any) -> Any:
             # 跳过内部字段
             if key in _TOOL_INPUT_INTERNAL_KEYS:
                 continue
-            # 跳过以 __ 开头的字段（Python 内部属性）
-            if key.startswith("__"):
+            # 跳过所有下划线前缀的内部字段（包含单下划线与双下划线）
+            if key.startswith("_"):
                 continue
             filtered[key] = value
 

agentrun/server/__init__.py

@@ -114,10 +114,10 @@
 ...     return "Hello, world!"
 """
 
+from ..utils.helper import MergeOptions
 from .agui_normalizer import AguiEventNormalizer
 from .agui_protocol import AGUIProtocolHandler
 from .model import (
-    AdditionMode,
     AgentEvent,
     AgentEventItem,
     AgentRequest,
@@ -166,7 +166,6 @@
     "ToolCall",
     # Event Types
     "EventType",
-    "AdditionMode",
     # Type Aliases
     "AgentEventItem",
     "AgentResultItem",  # 兼容别名
@@ -187,4 +186,6 @@
     "AGUIProtocolHandler",
     # Event Normalizer
     "AguiEventNormalizer",
+    # Helpers
+    "MergeOptions",
 ]