chore: import upstream snapshot with attribution

examples/canvas/langgraph-python/scripts/setup-agent.bat

@@ -0,0 +1,14 @@
+@echo off
+REM Navigate to the agent directory
+cd /d "%~dp0\..\agent" || exit /b 1
+
+REM Create virtual environment if it doesn't exist
+if not exist ".venv" (
+    python -m venv .venv
+)
+
+REM Activate the virtual environment
+call .venv\Scripts\activate.bat
+
+REM Install requirements using pip
+pip install -r requirements.txt