refactor: merge flight-wiki + restructure concepts/ into two subdirectories

- flight-wiki fully merged into airport-wiki/concepts/flight-operations/
- concepts/ restructured: tech-infrastructure/ (9 pages) + flight-operations/ (10 pages)
- aodb.md (380 lines) split into aodb-core.md + aodb-vendors.md
- SCHEMA.md updated: Domain covers '智算中心+航班運營' dual domains
- new: airport-systems-landscape.md (flight ops system architecture)
- index.md rewritten with visual directory tree
- log.md updated

airport-wiki/concepts/tech-infrastructure/tier-iii-design.md

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+---
+title: Tier III 数据中心设计
+created: 2026-04-08
+updated: 2026-04-08
+type: concept
+tags: [tier-iii, design]
+sources: []
+---
+
+# Tier III 数据中心设计
+
+## 标准参考
+
+- **ANSI/TIA-942-B**: 数据中心电信基础设施标准
+- **Uptime Institute Tier Standard**: 分为 Tier I/II/III/IV 四个等级
+
+## Tier III 核心要求
+
+- **可用性**: 99.98%（年停机 ≤ 1.6 小时）
+- **冗余等级**: N+1（可并行维护）
+- **电力路径**: 2N UPS 或 N+1 UPS 配置
+- **冷却系统**: N+1 冗余冷冻水系统或风冷系统
+- **网络接入**: 多运营商、多路由接入
+
+## 机场适用性
+
+机场主数据中心推荐采用 Tier III 级别，兼顾建设成本与业务连续性需求。
+
+> 相关：[[tier-iv-design]] | [[power-and-cooling]] | [[network-architecture]]