[feat] Add client_id support to task queue system

- Add client_id field to QueueTaskItem and TaskHistoryItem models
- Implement client-specific WebSocket message routing
- Add client filtering to queue status and history endpoints
- Follow ComfyUI patterns for session management
- Create data_models package for better code organization

comfyui_manager/data_models/__init__.py

@@ -0,0 +1,26 @@
+"""
+Data models for ComfyUI Manager.
+
+This package contains Pydantic models used throughout the ComfyUI Manager
+for data validation, serialization, and type safety.
+"""
+
+from .task_queue import (
+    QueueTaskItem,
+    TaskHistoryItem,
+    TaskStateMessage,
+    MessageTaskDone,
+    MessageTaskStarted,
+    MessageUpdate,
+    ManagerMessageName,
+)
+
+__all__ = [
+    "QueueTaskItem",
+    "TaskHistoryItem",
+    "TaskStateMessage",
+    "MessageTaskDone",
+    "MessageTaskStarted",
+    "MessageUpdate",
+    "ManagerMessageName",
+]