Addresses #23181
## Why
Renamed threads can share names, so hints that suggest resuming directly
by name are ambiguous. Issue #23181 asks for the picker hint to include
the thread name and thread ID in parens so users can disambiguate
safely.
## What
- Adds a shared resume hint formatter for named threads: run `codex
resume`, then select `<name> (<thread-id>)`.
- Uses that hint for /rename confirmations, TUI session summaries, and
CLI/TUI exit messages.
- Keeps direct `codex resume <thread-id>` guidance for unnamed threads.
## Verification
Manually verified that message after `/rename` and after `/exit` include
session ID in parens.
---------
Co-authored-by: Felipe Coury <felipe.coury@openai.com>
## Why
The TUI still had a few low-risk dependencies flowing through the
transitional `legacy_core` namespace after the app-server migration.
These helpers either already have clearer non-core owners or are
presentation logic that does not belong in `codex-core`, so moving them
out reduces the compatibility surface without changing product behavior.
## What changed
This is a low-risk change, almost completely mechanical in nature.
- Route TUI Codex-home lookup through `codex-utils-home-dir`, use
`Config::log_dir` directly, and call
`codex-sandboxing::system_bwrap_warning` without going through
`legacy_core`.
- Move shared `codex resume` hint formatting from `codex-core` into
`codex-utils-cli`.
- Update CLI and TUI call sites to use the shared CLI utility, and keep
the resume-command behavior covered by tests in its new home.
## Verification
- `cargo test -p codex-utils-cli`
- `cargo test -p codex-utils-cli resume_command`
