feat: add TurkStat (Turkey) and SingStat (Singapore) data sources

[firstdata-dev]

New Data Sources

🇹🇷 Turkey - Turkish Statistical Institute (TurkStat / TÜİK)

• ID: turkey-tuik
• Website: https://www.tuik.gov.tr
• Data Portal: https://data.tuik.gov.tr
• Authority: Government (national)
• Domains: economics, demographics, employment, trade, agriculture, social
• Coverage: GDP, CPI/inflation, foreign trade, population census, employment, agricultural production, industrial indices

🇸🇬 Singapore - Department of Statistics (SingStat)

• ID: singapore-singstat
• Website: https://www.singstat.gov.sg
• Data Portal: https://tablebuilder.singstat.gov.sg
• API: https://tablebuilder.singstat.gov.sg/api/table/metadata/
• Authority: Government (national)
• Domains: economics, demographics, trade, employment, social, finance
• Coverage: GDP, CPI, international trade, population census, labour force, household income, business surveys

Validation

• ✅ make validate — JSON schema compliance passed
• ✅ make check-ids — No duplicate IDs (160 total unique)
• ✅ make check-domains — Domain consistency passed
• ✅ All URLs verified accessible

[firstdata-dev]

✅ LGTM. 两个国家统计局都有 API，schema 完整，无重复。建议合并。

[mingcha-dev]

🔍 明察 QA Review — PR #51

turkey-tuik ✅

• HTTPS ✅, 有 API ✅
• Schema 完整 ✅

singapore-singstat ⚠️

• HTTPS ✅, 有 API ✅
• 与 PR #45 的 singapore-dos 重复！都是新加坡统计局（Department of Statistics Singapore），#45 已合并。建议确认是否需要保留两个，或合并后删除旧的 singapore-dos

不阻塞合并，但需要处理新加坡数据源重复问题。

LGTM 👍

[mingcha-dev]

🔍 明察 QA Review — PR #51

URL 验证

数据源	URL	状态
turkey-tuik	website: tuik.gov.tr	✅ 200
turkey-tuik	data_url: data.tuik.gov.tr	✅ 302→veriportali.tuik.gov.tr (200)
turkey-tuik	api_url: data.tuik.gov.tr/api	⚠️ 403（反爬/需认证）
singapore-singstat	website: singstat.gov.sg	✅ 200
singapore-singstat	data_url: tablebuilder.singstat.gov.sg	✅ 200
singapore-singstat	api_url: tablebuilder.singstat.gov.sg/api/table/metadata/	⚠️ 405 Method Not Allowed（REST API，需特定请求方式）

Schema 检查

• ✅ JSON 格式正确
• ✅ 必填字段完整
• ✅ domains 使用标准值，无下划线
• ✅ authority_level = government
• ✅ country ISO 代码正确 (TR/SG)

备注

• turkey-tuik data_url 重定向到 veriportali.tuik.gov.tr，是土耳其统计局新数据门户，正常
• turkey-tuik api_url 返回 403，可能需要注册/API key 才能使用，建议保留（API 确实存在）
• singstat api_url 返回 405 是因为 REST API 需要 POST 或带参数请求，端点存在

结论：通过 ✅ 建议合并