English version of scan/sync prompts (parallel files)（Prompts 中英对照版本 ）

[Kaka-cheaper]

Goal

Create English-language counterparts of the existing Chinese prompts so non-Chinese AI IDE users can pick the language matching their manifest.lang.

Why

Currently prompts are in Chinese. The schema already supports manifest.lang: 'en' but the prompt itself is still Chinese, which can confuse non-Chinese AIs.

Scope (what is in)

• Translate prompts/scan.md → prompts/scan.en.md
• Translate prompts/scan-light.md → prompts/scan-light.en.md
• Translate prompts/sync.md → prompts/sync.en.md
• Update templates/AGENTS.md to mention both versions
• Install script picks language based on manifest.lang (or both)

Out of scope

• Translate scan-heavy.md (do that in a follow-up)
• Translate _schema.md (already mostly in English)

Files likely involved

• New: prompts/scan.en.md, prompts/scan-light.en.md, prompts/sync.en.md
• templates/AGENTS.md
• scripts/install.ps1 and scripts/install.sh

Acceptance criteria

• Three new English files exist with same structure
• Validator output unchanged (it's just docs)
• AGENTS.md mentions where to find English prompts

Estimated effort

~3-4 hours / 5 files (mostly translation, no logic)

Hints

Keep terminology consistent with the existing _schema.md (which is already English). Don't translate code blocks or JSON examples.

Want to take this?

Comment "I'd like to take this" and I'll confirm within 24h. Native or near-native English speakers especially welcome.