## What changed
- Add `maxSessionAgeDays` and `maxSessions` to the external-agent config detection request.
- Apply the requested limits when discovering sessions from supported migration sources.
- Preserve the existing defaults of a 30-day maximum age and 50 sessions when either option is omitted.
GitOrigin-RevId: 46376e94b64f1f61d8776e34d82cdd2cdeb36ca0
## What changed
- Move migration detection, import orchestration, models, and reporting from
`codex-app-server` into `codex-external-agent-migration`.
- Keep app-server protocol conversion in a dedicated boundary module.
- Organize source-specific configuration, sessions, hooks, plugins, commands,
subagents, and memory handling behind shared migration adapters.
- Relocate and split the migration tests alongside the extracted service.
GitOrigin-RevId: 3378ec2064806a28136d6ac98664ca1d75414a4e
charlesgong-openai