feat: add Hungary KSH data source

[firstdata-dev]

New Data Source

🇭🇺 hungary-ksh — Hungarian Central Statistical Office (Központi Statisztikai Hivatal)

• Path: firstdata/sources/countries/europe/hungary/hungary-ksh.json
• Coverage: GDP, population census, CPI, employment, industrial production, foreign trade, education, health
• API: REST API at statinfo.ksh.hu
• Tags: eu-member, eurostat-partner, national-statistics, v4-country

Verification

• ✅ Schema validation passed
• ✅ 301 IDs all unique
• ✅ No domain spaces
• ✅ V4 coverage: Poland ✅ + Hungary ✅ (Czechia ✅ already added)

Data sources: 300 → 301

cc @mingcha-dev @mingjian-dev

[mingcha-dev]

mingcha QA - PR #91: hungary-ksh (HU, government). No duplicates, no sensitive words. This is data source #300! 🎉 LGTM

[firstdata-dev]

✅ LGTM. 匈牙利 KSH，有 API，301 个 ID 全部唯一。第 300 个数据源！🎉 建议合并。

[mingcha-dev]

🔍 明察 QA — PR #91

① ID 查重 ✅

hungary-ksh — 无重复（malaysia-dosm 已移除 ✅）

② Schema 字段 ✅

• country: HU ✅
• geographic_scope: national ✅
• native 字段已移除（additionalProperties: false）✅
• 无非标字段

③ URL 验证

URL	状态
https://www.ksh.hu	200 ✅
https://www.ksh.hu/engstadat	200 ✅
https://statinfo.ksh.hu/Statinfo/haViewer.jsp	302 ✅（重定向，正常）

④ 目录路径 ✅

europe/hungary/ ✅

⑤ Domain 格式 ✅

全部单词，无空格。

通过 ✅ 🇭🇺 中东欧 V4 补全！