Update langgraph.json to include dot env file inherently

[kushalhalder]

No description provided.

[jondmarien]

This change to include the .env file path in langgraph.json looks good and should help resolve configuration issues like those mentioned in #11. The relative path './.env' is appropriate for the project structure.

However, since this changes how configuration is loaded, it would be helpful to:

1. Update the README to document this change
2. Consider adding a .env.example file to show required variables

Otherwise, the change itself looks correct and is a good improvement.

[jondmarien]

The changes look good and will improve the configuration experience. The addition of the env path in langgraph.json is a sensible solution for handling environment variables.

Once the documentation updates are added as suggested in the previous comment, this will be ready to merge.

[mdrxy]

@kushalhalder please provide a description