The terminal's migrate sorts each account's repositories by last push, previews a pasted URL, and migrates several at once, like /migrate #6229

Part of the owner's #5816. On /migrate the web page leads with the paste field and a picker (the issue this waits for). The terminal is the same door, and reviewers asked that it work the same way.

Done when:

• [ ] In the terminal's migrate screen, each account's repositories are listed newest push first and filter as you type.
• [ ] Pasting a URL shows the host and repository before you confirm, plus size and visibility when the repository is one of your accounts'. It reads the same function the page reads.
• [ ] You can mark several repositories (Space marks, Enter migrates the marked ones, up to 20). Each starts under its own name, with the same refusals as the page's "Migrate selected".
• [ ] The README's terminal section says how.
• [ ] A test drives the terminal screen: the sort order, the preview line for a pasted URL, and two marked repositories starting two migrations.

Files: src/tui/screens/migrate.ts, the shared reads in src/web/pages/migrate.ts (moved to a module both use, if needed), README.md, a test.

Parked by the steward, 2026-10-26 (owner: "get us unclogged now then resume everything else"). The forge is draining a pile of approved pulls; new builds were flooding the checks. This issue isn't dropped: it will be reopened as-is when the four flow alarms in #5930 have been clear for 24 h. The list is kept in the steward's parked-2026-10-26 file.

Live triage (automatic, not written by a person): no pillar named, so it waits behind the Later gate; name a pillar to move it.