feat(world-lab): add agent behavior trace

[christopherjnelson]

Summary

• derive a bounded, newest-first behavior trace from retained agent turn records
• show observation changes, retained evidence, legal versus chosen actions, action patterns, and continuity outcomes
• add browser-only map highlighting and sticky Agent Inspector navigation
• document the read-only, non-causal architecture boundary and add focused coverage

Validation

Repository owner confirmed the full local gate is green:

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