[codex] Parallelize skills list cwd loading

[xli-oai]

Summary

• process skills/list cwd entries with bounded concurrency of 5
• preserve the caller's requested cwd order in the response
• add coverage that verifies response ordering remains stable

Why

Cold-start desktop traces showed that skills/list can dominate the shared config queue when it scans many workspace roots serially. The expensive work is largely independent per cwd, so the request was paying the sum of all cwd costs instead of the cost of the slowest bounded batch.

Impact

This keeps current request semantics intact while reducing the wall-clock time of large multi-root skills/list calls. That should also reduce how long later config-family requests, such as plugin/list, wait behind skills/list during startup.

Validation

• just fmt
• cargo test -p codex-app-server
• cargo test -p codex-app-server skills_list_preserves_requested_cwd_order

[xli-oai]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. What shall we delve into next?

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".