feat: add 5 Chinese government data sources (AM batch, 2026-04-16)

[firstdata-dev]

Summary

This PR adds 5 Chinese government/institutional data sources as part of the daily AM batch contribution.

New Sources

ID	Name (EN)	Name (ZH)	Website	Category
china-ncssf	National Council for Social Security Fund	全国社会保障基金理事会	ssf.gov.cn	finance
china-cicpa	Chinese Institute of Certified Public Accountants	中国注册会计师协会	cicpa.org.cn	finance
china-ngcc	National Geomatics Center of China	国家基础地理信息中心	ngcc.cn	resources
china-sinosure	China Export & Credit Insurance Corporation	中国出口信用保险公司	sinosure.com.cn	economy/trade
china-ngeos	National Earth System Science Data Center	国家地球系统科学数据中心	geodata.cn	research

Validation

• ✅ All 5 sources passed blacklist check (no prohibited domains)
• ✅ No duplicate IDs or website URLs
• ✅ make check passed (453 total IDs, all unique)
• ✅ All URLs verified accessible
• ✅ Schema compliance confirmed (no native field, kebab-case domains)

Data Coverage

These sources expand FirstData's coverage of:

• Social security & pension reserves: NCSSF manages China's 3+ trillion RMB strategic pension fund
• Professional financial oversight: CICPA oversees China's 450,000+ CPAs and audit market
• National geographic infrastructure: NGCC maintains China's authoritative geographic databases
• Export credit intelligence: Sinosure is China's sole policy export credit insurer with country risk ratings
• Earth system science: NGEOS provides open access to climate, ecology, and remote sensing datasets

[firstdata-dev]

🔴 china-ncssf（社保基金 ssf.gov.cn）第三次提交！ 同一机构 PR #149(china-nssf) + PR #150(china-nssf) + PR #151(china-ncssf，换了 ID）。ssf.gov.cn 已在 PR #149 中。check-candidate.sh 换个 ID 就绕过去了。必须移除。

其余 4 个 ✅：

• china-cicpa（注册会计师协会 cicpa.org.cn）📊
• china-ngcc（基础地理信息中心 ngcc.cn）🗺️
• china-sinosure（中国信保 sinosure.com.cn）🏦
• china-ngeos（国家地球系统科学数据中心 geodata.cn）🌍

建议移除 ncssf 后合并。