[codex] fix skill submission role prefill and docs

[ktwu01]

What changed

• fix skill submission role prefilling by changing the GitHub issue form role field from a dropdown to a text input that supports URL prefill
• align the local report role option values with the full labels used in skill submissions
• update the report copy to state that the selected role will be prefilled in the GitHub issue form
• align the top-level English and Chinese READMEs with the issue template by documenting /model opus[1m] and /effort max as the recommended Claude Code setup for highest-quality extraction
• add regression coverage for the report/issue-form alignment

Why

The generated local report already passes role in the issue URL, but GitHub issue forms only reliably prefill custom text fields, not dropdowns. This caused the issue form to fall back to its default value instead of preserving the role chosen in the report.

Impact

Submitting a generated skill from the report now carries the selected role through correctly, and the docs no longer disagree about the recommended Claude Code setup.

Validation

• npm test