English-facing: README and commit messages

This repo is public and read by outsiders (an interviewer, among others). Two surfaces must always be English:

• README.md — the front page.
• Commit messages — the whole message, subject and body, and any PR description.

That's the whole rule. Set 2026-09-17, after the entire history was translated to English once.

What is NOT covered

• Code comments stay as they are (this repo has dense Chinese comments across src/). Don't translate them, and don't start writing new comments in English just because of this rule — match the file you're editing.
• Other docs (docs/*, skill files, etc.) keep their current language. docs/NOTES.md and CLAUDE.md happen to be English now; a doc that is Chinese stays Chinese unless the user asks.

If in doubt about a surface not listed above, leave its language alone.

Chinese as data is fine

The rule is that the prose is English, not that Chinese characters are banned. A commit message may — and sometimes must — quote Chinese that is data:

• a real filename or title the change touches (Full passport_LL.pdf, _哔哩哔哩_bilibili),
• a query or string the system processes, when it's the point (今天做了什么 returning nothing, the bigram cut of 报错 into 报错 / 错截 / 截图),
• a place name or example demonstrating multilingual behaviour (泰晤士河 ↔ Thames).

Stripping those would destroy the meaning. Keep them; write the sentence around them in English.

Commit message style

Follow the existing git log: say why, not just what, and give the measured numbers that made it the decision. Keep the attribution line the harness/CLAUDE.md specifies.

If asked to translate history again

The one-time job (translate all Chinese commit messages, re-point the release tags, force-push) was done once. If it's ever needed again: back up first (git bundle create <file> --all), build a SHA → new message map, rewrite with git filter-branch --msg-filter … --tag-name-filter cat -- main v1.0.0 v1.0.1 (git-filter-repo isn't installed), and remember that force-pushing rewritten history to a public repo means any other clone must reset, not pull.