codex - 💡(How to fix) Fix TUI slash popup opens for fuzzy-only input but shows no matches [1 participants]

Summary

The TUI slash-command popup can open for fuzzy-only input even though the popup itself now filters commands by exact/prefix match only.

For example, /ac is a fuzzy subsequence match for commands like compact, so looks_like_slash_prefix opens the command popup. The popup's filtered() method then applies exact/prefix filtering and returns no items, leaving a visible popup with no matches.

This is not a request to restore fuzzy slash-command matching. The change keeps the prefix-only behavior consistent and prevents opening an empty popup for inputs that the popup cannot display.

Reproduction

1. Start the TUI.
2. Type /ac in the composer.
3. Observe that the command popup opens but shows no matches.

Patch

Slash-popup-specific diff, stacked on the compile fix from #21394:

https://github.com/misrtjakub/codex/compare/fix/tui-add-to-history-command...fix/tui-slash-popup-prefix-only-stacked?expand=1

Stacked branch against upstream main:

https://github.com/openai/codex/compare/main...misrtjakub:fix/tui-slash-popup-prefix-only-stacked?expand=1

The stacked branch includes #21394 because current origin/main does not compile codex-tui with Cargo without that missing AddToHistory fix.

Validation

cargo test -p codex-tui builtin_prefix_matching_is_prefix_only
cargo test -p codex-tui slash_popup_activated_for_bare_slash_and_valid_prefixes
cargo fmt --check
git diff --check