Update Documentation and Project Files

[jethronap]

Update all project documentation to reflect the new LangChain architecture and provide migration guidance.

Update README.md with new architecture overview and setup instructions
Update WARP.md with LangChain-specific development guidance:

• Agent development patterns
• Tool creation guidelines
• Memory and caching system
• Debugging and observability
  Create MIGRATION.md documenting changes from v0 to v1
  Update .env-sample with all required LangChain variables
  Create docs/langchain-architecture.md with detailed technical documentation
  Update code comments and docstrings throughout codebase

Files to Create/Modify:

• README.md
• WARP.md
• MIGRATION.md (new)
• .env-sample
• docs/langchain-architecture.md (new)