[Pigbibi]

Summary

Documentation-only change. Align README.md and README.zh-CN.md with the
QuantStrategyLab documentation style guide.

Why

The previous READMEs described internal process, listed internal documents, and
diverged between English and Chinese, with the Chinese file carrying details the
English file lacked.

Changes

• Rewrite the English README to the required section order (Status, What this
  is, What this is not, Quick start, Configuration, Repository layout,
  Contributing, Security, License).
• Add a matching Simplified Chinese README with the same sections, order,
  commands, links, and configuration names.
• Present runtime environment variables as a configuration table with required
  and default columns, using placeholders for bucket and project identifiers.
• Remove the monthly API review process notes and internal document links.

Testing

No code changed. Verified both files against the style-guide checklist and grep
list: no absolute home paths, non-placeholder buckets, personal subdomains,
40-character hex strings, status tables, dated audit titles, or process
narration. Confirmed the two files have the same sections in the same order.

Risk and rollback

Docs only. Revert the commit to roll back.

Breaking changes

none