## Why
Users need to understand what external-agent data Codex detected, what
is selected, and how to proceed before an import begins. The updated
picker makes focus, selection state, and the submission path explicit
while preserving the existing import backend.
## What changed
- replace the old migration prompt with a two-step external-agent import
picker
- add a customize view with explicit item focus, selection state,
counts, and a review action
- separate detected import data into a view model
- add Unix and Windows snapshots for prompt, item-focus, and
action-focus states
## Validation
- `just test -p codex-tui external_agent_config_migration` (10 passed)
- manually exercised an isolated TUI fixture covering customization,
selection toggles, review, import, repeated invocation, and session
resume
- the broader `just test -p codex-tui` run passed 2,805 tests, with 2
unrelated guardian feature-flag failures and 4 skipped tests
## Review note
This is the largest layer in the stack because the interaction state,
rendering changes, and required snapshots move together. It remains a
draft in case reviewers prefer a further presentation/state split.
## Stack
1. [#27064](https://github.com/openai/codex/pull/27064): remove the
startup migration flow
2. [#27065](https://github.com/openai/codex/pull/27065): extract the
picker renderer
3. [#27070](https://github.com/openai/codex/pull/27070): add the
external-agent import picker UX
4. [#27071](https://github.com/openai/codex/pull/27071): expose the flow
through `/import`
**This PR is stack item 3.** Draft while the lower stack dependencies
are reviewed.
stefanstokic-oai
e3528434cd