## What changed
Measure thread storage before and after `codex migrate-rollouts --apply` and
include the formatted sizes in the human-readable migration report. The total
includes active and archived rollout files, the thread history database, and
its WAL and shared-memory sidecars.
Keep dry-run and JSON output unchanged, and omit the storage summary if either
measurement fails.
GitOrigin-RevId: 1775c0b6849570a814becd94e196dd05908667a1