feat: add new examples from pocketflow-academy

cookbook/pocketflow-tool-pdf-vision/utils/call_llm.py

@@ -0,0 +1,9 @@
+import os
+from openai import OpenAI
+from pathlib import Path
+
+# Get the project root directory (parent of utils directory)
+ROOT_DIR = Path(__file__).parent.parent
+
+# Initialize OpenAI client with API key from environment
+client = OpenAI(api_key=os.getenv("OPENAI_API_KEY"))