fix: preserve bounded agent factual history

[christopherjnelson]

Summary

• retain independent bounded factual histories for agent observations instead of deriving them from the shared 120-event display feed
• preserve participant-scoped privacy for direct, alliance, and Patient Zero messages
• ingest complete committed event batches while keeping cancellation, reset, and World Setup boundaries safe
• keep cleaner-threat history on its dedicated ledger and leave schemas, exports, providers, UI, and gameplay unchanged

Testing

Owner confirmed the complete local validation suite is green:

• pnpm format
• pnpm format:check
• pnpm lint
• pnpm typecheck
• pnpm test
• pnpm build
• pnpm test:e2e