feat(adapter): add LangGraph export and run adapter

[dahlinomine]

Summary

Adds langgraph as a new export format and run adapter.

Closes #1.

Changes

• src/adapters/langgraph.ts — exports a gitagent directory as a LangGraph StateGraph Python script using the ReAct pattern with ToolNode and conditional routing
• src/runners/langgraph.ts — runs the exported graph script via python3
• Multi-agent topology: sub-agents defined in agent.yaml are annotated with guidance for LangGraph supervisor-node patterns
• Compliance constraints (FINRA 2210, 17a-4, SOD conflicts) are injected into the system SYSTEM_PROMPT constant
• Model routing: gpt-4o default, claude-* → ChatAnthropic, gemini-* → ChatGoogleGenerativeAI

Usage

# Export to a LangGraph Python script
gitagent export -f langgraph -d ./my-agent -o agent_graph.py

# Run directly
gitagent run -a langgraph -d ./my-agent

Generated output example

Given an agent with a research skill and claude-3-5-sonnet-20241022 model:

from langgraph.graph import StateGraph, END
from langgraph.prebuilt import ToolNode
from langchain_anthropic import ChatAnthropic

class AgentState(TypedDict):
    messages: Annotated[Sequence[BaseMessage], operator.add]

@tool
def research(input: str) -> str:
    """Research a topic..."""
    raise NotImplementedError("research not yet implemented")

tools = [research]
llm = ChatAnthropic(model="claude-3-5-sonnet-20241022", temperature=0.3)
llm_with_tools = llm.bind_tools(tools)
# ... StateGraph wiring ...
graph = workflow.compile()

Testing

• npm run build passes
• gitagent export -f langgraph -d examples/standard produces valid Python
• gitagent export -f langgraph -d examples/full renders compliance constraints

Checklist

• Follows the existing adapter pattern (crewai, openai, lyzr)
• Runner follows the existing runner pattern (runners/openai.ts)
• Wired into adapters/index.ts, commands/export.ts, commands/run.ts
• No new dependencies added
• Conventional commit message

[shreyas-lyzr]

can we create a adapter for DeepAgents instead? https://docs.langchain.com/oss/python/deepagents/overview