docs: 重建 PKR 知识库文档（21篇能力 + 4篇规范） - #208

重构 PKR 文档结构，从扁平目录改为模块化子目录：

能力文档（22篇）：

• springboot-starter (7): event-system, response-dto, domain-proxy, page-request, exception-handling, locale-message, rest-client
• springboot-starter-security (1): auth-gateway
• springboot-starter-data-fast (1): fast-repository
• springboot-starter-data-authorization (1): sql-interception
• springboot-starter-flow (1): workflow-engine
• springboot-starter-script (1): groovy-runtime
• 框架能力 (10): springboot/ioc-container, springboot/data-jpa, springboot/security, alibaba/fastjson, jsonwebtoken/jjwt, apache/groovy, jsqlparser/jsqlparser, esotericsoftware/kryo, react/react, redux/toolkit

规范文档（5篇）：

• event-driven-convention, response-convention, ddd-layered-architecture, exception-handling-convention, dynamic-query-convention

导出文档（17篇）：

• docs/agents/ 供下游项目导入使用

更新 CLAUDE.md：注入 PKR 知识查阅约束

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