docs: capture remaining Claude Code test oracles

[bingran-you]

Summary

• add transcript-search render-fidelity and managed-settings early-read test oracles
• tighten cross-surface permission semantics so local, headless, remote, and hook approval paths stay lockstep
• document fixture replay fidelity for usage accounting and resume-safe runtime identities

Validation

• npx -p first-tree first-tree verify