## Why
When the TUI resumes a thread, transcript replay renders prior user
messages but did not seed the composer history. That leaves the resumed
session with empty in-memory prompt history, so pressing Up can fall
through to persisted global history and surface a prompt from another
thread.
The expected behavior is that prompts from the resumed thread are
recalled first, with global history only as a fallback.
## What changed
- Record replayed user messages into the composer history during resume
replay.
- Preserve the existing persisted history format and avoid any startup
history scan.
- Add focused TUI coverage showing replayed prompts are recalled before
persisted global history.
## Validation
- Added `replayed_user_messages_seed_composer_history` in
`codex-rs/tui/src/chatwidget/tests/history_replay.rs`.
- `just test -p codex-tui replayed_user_messages_seed_composer_history`
passed.