refactor: 重构文档结构和文件位置

docs: 添加Redis集成测试文档
docs: 添加ID生成器分析报告
docs: 添加自由布局和固定布局示例文档
test: 添加ID生成器单元测试
fix: 删除重复的前端文档文件

docs/test/flow_create.json

@@ -0,0 +1,3 @@
+{
+  "yaml": "# demo flow\nnodes:\n  - { id: start, kind: start, name: 开始 }\n  - { id: assign, kind: custom, name: 赋值, script: ctx.x = ctx.x + 1; }\n  - { id: cond, kind: custom, name: 条件 }\n  - { id: end, kind: end, name: 结束 }\nedges:\n  - { from: start, to: assign }\n  - { from: assign, to: cond }\n  - { from: cond, to: end, condition: ctx.x >= 1 }\n  - { from: cond, to: end }\n"
+}