- Add v3.16.4 release notes in zh/en/ja.
- Add a trilingual FAQ explaining why custom models don't show in the Codex desktop model picker (upstream Codex Desktop login-identity gating, not a cc-switch bug) and the keep-official-login mitigation; cross-linked both ways with the official-auth preservation guide.
- Align the CHANGELOG 3.16.4 release date to 2026-06-27.
New zh/en/ja guide for the unified Codex session-history toggle: what opt-in migration (on enable) and ledger-based restore (on disable) actually do, why session data is never truly deleted (tag-only rewrite + automatic backups), and how to verify files on disk versus just being filed under another provider drawer. Includes a symptom reference table for the common "my sessions are gone" misunderstanding and on-disk verification commands for macOS/Linux/Windows.
Link the guide as the lead item in the "Usage Guides" section of the v3.16.3 release notes (zh/en/ja).
Jason