Vim mode switches from Normal to Insert after cancelling slash command with Backspace

What happened?

When Codex TUI Vim mode is in Normal, opening the slash command picker with / and then deleting the slash with Backspace changes the composer state to Vim: Insert.

This feels unexpected because cancelling the slash command picker should preserve the Vim mode that was active before opening it.

Steps to reproduce

1. Start Codex CLI.
2. Enable Vim mode with /vim.
3. Ensure the composer shows Vim: Normal.
4. Press / to open the slash command picker.
5. Press Backspace to delete/cancel the slash input.

Actual behavior

The composer switches to Vim: Insert.

Expected behavior

The composer should return to the previous Vim state, i.e. Vim: Normal in this repro.

More generally:

• If the slash command picker was opened from Vim: Normal, cancelling it should return to Vim: Normal.
• If it was opened from Vim: Insert, cancelling it should return to Vim: Insert.

Environment

• Codex CLI: codex-cli 0.130.0
• OS: Linux x86_64, Ubuntu kernel 6.8.0-49-generic
• Terminal: running inside tmux, TERM=screen

Notes

Using Esc after the transition returns to Vim: Normal, so this is mainly a Vim-mode state restoration issue after cancelling the slash command picker with Backspace.