Build deterministic closed simulation engine

[maximalfocus]

Summary

• scaffold the static React and TypeScript application with repository-native CI gates
• add a reusable pure simulation engine and authored six-beat “The Stuck Agent” scenario
• model deterministic events, agents, notes, fictional infrastructure state, metrics, and closed transition preconditions
• reject unsupported scenario versions/configuration and keep all network-like behavior inside bundled fictional data

Verification

• npm test — 5 tests passed
• npm run typecheck — passed
• npm run lint — passed
• npm run build — passed
• git diff --check — passed
• safety API scan — no fetch, HTTP client, process execution, arbitrary URL, or real credential handling found

Closes #1