docs: synchronize English and Chinese READMEs

[Pigbibi]

Summary

Documentation-only: synchronize the English and Simplified Chinese READMEs with the organization documentation style guide.

Why

The Chinese README lacked configuration and HTTP endpoint details. Both guides needed the standard section order and language links.

Changes

• Use matching sections, commands, configuration tables, and HTTP endpoint references in both languages.
• Explain local input handling, profile selection, and the existing offline dry-run and paper-admission behavior.
• Replace the fixed digest example with a placeholder and add contribution, security, and license links.

Testing

Passed git diff --check and static checks for local links, command paths, balanced Markdown fences, Bash syntax, matching bilingual sections and command blocks, and added-content privacy patterns. Verified the documented settings, routes, and lifecycle behavior against the current implementation. No runtime tests were run locally because only the two README files changed. CI: test workflow.

Risk and rollback

Documentation-only change. Revert the commit to restore the previous README text.

Breaking changes

none

Checklist

• This PR follows the documentation style guide.
• Documentation-only changes say so in the Summary.