Define LangGraph State Workflow

from typing import TypedDict, Annotated
from langgraph.graph import StateGraph, END
from langchain_core.tools import tool

class PdmState(TypedDict):
    plant_id: str
    vibration_data: dict
    health_status: str
    rul_days: int
    trigger_wo: bool

# Create workflow graph nodes for ISO evaluation and CMMS dispatch