[Flow] Document first‑run onboarding and trust flow — TUI #42
Description
Summary
New users experience a trust/onboarding sequence (approvals/sandbox, workspace trust). Provide a step‑by‑step doc with screenshots and expected states to reduce confusion and support troubleshooting.
Current vs Expected
- Current: Onboarding code exists (tui/src/onboarding/*) and some behaviors are noted in docs, but no end‑to‑end walkthrough.
- Expected: A concise “First Run” guide with visuals showing prompts, options, and where settings surface in UI.
Proposed Changes
- Add a “First Run” doc under docs/ with screenshots of each step.
- Clarify where sandbox/approval policies are displayed (History panel summary) and how to change them.
- Link from Getting Started and README.
Acceptance Criteria
- New doc with at least: trust directory step, approvals/sandbox presets picker, status indicators.
- README and docs/getting-started.md link added.
- Troubleshooting section for common blockers (permissions, terminal quirks).
References
- codex-rs/tui/src/onboarding/*, codex-rs/tui/src/history_cell.rs