[nightly-maintenance] Document smoke command wrappers

[r3dbars]

Summary

• list the existing root E2E and live-capture smoke wrappers in the command surface docs
• mirror those wrapper implementation paths in scripts/README.md

Validation

• scripts/dev/agent-preflight.sh
• git diff --check

[r3dbars]

verdict: no-findings-but-human

findings: none from this pass.
actions: human signoff recommended because the PR is still draft, though the docs-only command-surface update looks low risk.
head_sha: 0b39f84
fix_commit: none
checks: gh pr view, gh pr diff, repo-layout/scripts docs read, root smoke wrappers checked, git diff --check origin/main...origin/codex/nightly-maintenance-smoke-command-docs-20260520; GitHub checks reported none.

manual_merge_handoff:
head_sha: 0b39f84
verdict: no-findings-but-human
blockers: draft PR needs human signoff
checks: gh metadata/diff, local docs/static review, wrapper existence check, diff check