Refine Turnkey rate-limit detection

[RAprogramm]

Summary

• tighten the Turnkey rate-limit heuristics to require explicit phrases and avoid partial word matches
• extend the Turnkey tests with regressions that keep corporate/operational texts in the correct categories
• bump the crate version to 0.10.9 and document the change in the changelog and README

Testing

• cargo +nightly fmt --
• cargo +1.90.0 clippy -- -D warnings
• cargo +1.90.0 build --all-targets
• cargo +1.90.0 test --all
• cargo +1.90.0 doc --no-deps
• cargo audit
• cargo deny check

---

https://chatgpt.com/codex/tasks/task_e_68cf49019fb0832b8fadb8ec655de585

[chatgpt-codex-connector]

Codex Review: Here are some suggestions.

Reply with @codex fix comments to fix any unresolved comments.

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, or 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 fix this CI failure" or "@codex address that feedback".