feat(docs): restructure API design guide with interactive demos and practical examples

refactor(components): replace static API design components with interactive demos
- Add ApiRequestDemo, RestfulUrlDemo, StatusCodeDemo, ErrorHandlingDemo, and ApiVersioningDemo
- Remove outdated ResourceAnalogy, RequestStructureDemo, and VersioningStrategyDemo

docs(api-design): completely rewrite API design chapter with restaurant analogy
- Add clear problem scenarios and solutions
- Include practical e-commerce API examples
- Add terminology glossary
- Improve error handling and versioning sections

style(ai-history): enhance FoundationDemo with better visual hierarchy
- Add section blocks for core theories and early breakthroughs
- Improve typography and highlighting

chore: remove unused components (CpuArchitectureDemo, EvolutionFlowDemo)

docs/.vitepress/config.mjs

@@ -629,8 +629,8 @@ export default defineConfig({
                 { text: 'HTTP 协议', link: '/zh-cn/appendix/4-server-and-backend/http-protocol' },
                 { text: '一个请求的完整旅程', link: '/zh-cn/appendix/4-server-and-backend/request-journey' },
                 { text: 'Web 框架的本质', link: '/zh-cn/appendix/4-server-and-backend/web-frameworks' },
-                { text: 'API 设计哲学（REST / GraphQL / gRPC）', link: '/zh-cn/appendix/4-server-and-backend/api-design' },
                 { text: 'API 入门', link: '/zh-cn/appendix/4-server-and-backend/api-intro' },
+                { text: 'API 设计哲学（REST / GraphQL / gRPC）', link: '/zh-cn/appendix/4-server-and-backend/api-design' },
                 { text: '序列化与数据格式', link: '/zh-cn/appendix/4-server-and-backend/serialization' },
                 { text: '认证与授权体系', link: '/zh-cn/appendix/4-server-and-backend/auth-authorization' },
                 { text: '并发、异步与多线程', link: '/zh-cn/appendix/4-server-and-backend/concurrency-async' },