Python: feat: Add ChatKit integration with a sample application (#1273)

* feat: Add ChatKit integration with a new frontend application

- Created a new frontend application using React and Vite for the ChatKit integration.
- Added essential files including package.json, vite.config.ts, and Tailwind CSS configuration.
- Implemented core components: App, Home, ChatKitPanel, ThemeToggle, and hooks for color scheme management.
- Established SQLite-based store implementation for ChatKit data persistence in store.py.
- Integrated theme toggling functionality for light and dark modes.
- Set up ESLint and TypeScript configurations for better development experience.

* git ignore

* fix mypy

* add mising file

* minimal frontend for chatkit sample

* update ignore files

* version

* set python version lowerbound on chatkit

* update project settings for chatkit

* update setup

* update setup

* update setup

* update setup

* weather widget

* add select city widget sample

* remove widget helper

* update chatkit to include file attachments and cover more thread item types

* update readme with mermaid diagram

* update diagram

* update instructions

* update chatkit dependency

* fix converter imports

* move to demos/

* move to demos/ -- rename references

* support multiple session instead of using global variable in sample

* support chunk streaming

* fix tests

* Update python/samples/demos/chatkit-integration/store.py

Co-authored-by: Evan Mattson <35585003+moonbox3@users.noreply.github.com>

* use local host

---------

Co-authored-by: Evan Mattson <35585003+moonbox3@users.noreply.github.com>

python/packages/core/agent_framework/chatkit/__init__.py

@@ -0,0 +1,23 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+import importlib
+from typing import Any
+
+PACKAGE_NAME = "agent_framework_chatkit"
+PACKAGE_EXTRA = "chatkit"
+_IMPORTS = ["__version__", "ThreadItemConverter", "simple_to_agent_input", "stream_agent_response"]
+
+
+def __getattr__(name: str) -> Any:
+    if name in _IMPORTS:
+        try:
+            return getattr(importlib.import_module(PACKAGE_NAME), name)
+        except ModuleNotFoundError as exc:
+            raise ModuleNotFoundError(
+                f"The '{PACKAGE_EXTRA}' extra is not installed, please do `pip install agent-framework-{PACKAGE_EXTRA}`"
+            ) from exc
+    raise AttributeError(f"Module {PACKAGE_NAME} has no attribute {name}.")
+
+
+def __dir__() -> list[str]:
+    return _IMPORTS

python/packages/core/agent_framework/chatkit/__init__.pyi

@@ -0,0 +1,10 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+from agent_framework_chatkit import (
+    ThreadItemConverter,
+    __version__,
+    simple_to_agent_input,
+    stream_agent_response,
+)
+
+__all__ = ["ThreadItemConverter", "__version__", "simple_to_agent_input", "stream_agent_response"]