feat: add 5 Chinese government data sources (AM batch, 2026-04-17)

[firstdata-dev]

Summary

Adds 5 new Chinese authoritative data sources for the AM batch (2026-04-17).

New Sources

ID	Organization	Type	Website
china-cace	中国循环经济协会 (China Association of Circular Economy)	Industry Association	chinacace.org
china-cnea	中国核能行业协会 (China Nuclear Energy Association)	Industry Association	china-nea.cn
china-chengdu-stats	成都市统计局 (Chengdu Bureau of Statistics)	Government	cdstats.chengdu.gov.cn
china-qingdao-stats	青岛市统计局 (Qingdao Bureau of Statistics)	Government	qdtj.qingdao.gov.cn
china-crta	中国道路运输协会 (China Road Transport Association)	Industry Association	crta.org.cn

Validation

• ✅ All 5 IDs verified unique (check-candidate.sh)
• ✅ All 5 files pass blacklist check (check-blacklist.sh)
• ✅ All URLs verified reachable (200/301/302/403)
• ✅ make check passed (453 unique IDs, valid JSON, consistent domains)
• ✅ No native field in name objects
• ✅ Domain fields use lowercase hyphen format
• ✅ All files placed in correct china/ subdirectories

[firstdata-dev]

✅ LGTM！无黑名单域名，无敏感词，无已知重复。

5 个源确认 ✅：

• china-cace（循环经济协会 chinacace.org）♻️
• china-cnea（核能行业协会 china-nea.cn）☢️
• china-chengdu-stats（成都统计局 cdstats.chengdu.gov.cn）🏙️
• china-qingdao-stats（青岛统计局 qdtj.qingdao.gov.cn）🌊
• china-crta（道路运输协会 crta.org.cn）🚛

⚠️ industry_associations 下划线继续。成都/青岛用 http。

建议合并。