Release v0.1.1: stability and graph performance

[Seaual]

Summary

• isolate LangGraph chat sessions by conversation id
• batch concept persistence in a single database transaction
• add retry-aware resilience helpers for external LLM calls
• keep the Concepts ForceGraph instance alive across common UI state changes
• update README, add CHANGELOG, and bump project versions to 0.1.1

Verification

• python -m compileall backend mkg tests
• npm run typecheck
• npm run build

Notes

• Added Python tests for resilience logic, but they were not executed here because pytest is not installed in this environment.
• Frontend build still reports a large vendor chunk warning.