feat(pvisor): add Codex SandboxReplay resume bridge

[wyeth93]

Summary

• add Codex native rollout replay and isolated session continuation
• add a local Responses bridge that removes resume transport nonce before forwarding
• clean transport-only messages from continued trajectories and preserve explicit boundary prompts
• update SandboxReplay CLI/reference documentation and Codex replay results

Validation

• cargo fmt --all -- --check
• cargo test -p persisting-replay adapter::generic::tests -- --nocapture
• cargo test -p persisting-replay --test replay_contract -- --test-threads=1
• cargo test -p persisting-replay codex_bridge -- --nocapture
• cargo build -p persisting-pvisor --release
• docs/.venv/bin/python -m mkdocs build --strict --config-file docs/mkdocs.yml

Rebased onto the latest upstream main before submission.