solve the prompt errors

wit error in processing story

Enhance SdlcNode with JSON validation and retry logic for design document generation; improve error handling and logging for user stories and design documents.

PMPT

Refactor design document prompts in SdlcNode; update prompt library with new prompt strings for design documents; adjust message formatting for improved clarity.

Refactor SDLC graph builder to remove memory checkpointer; add prompt library for user stories; update Streamlit UI for project details input; enhance project details handling in session state.