chore: 初始版本提交 - 简化架构 + 轮询改造

- 移除 Motia Streams 实时通信，改用 3 秒轮询
- 简化前端代码，移除冗余组件
- 简化后端架构，准备 FastAPI 重构
- 更新 pixi.toml 环境配置
- 保留 bttoxin_digger_v5_repro 作为参考文档

Co-Authored-By: Claude <noreply@anthropic.com>

motia-backend/pixi.toml

@@ -0,0 +1,33 @@
+[workspace]  
+authors = ["hotwa <pylyzeng@gmail.com>"]  
+channels = ["conda-forge", "bioconda"]  
+name = "motia-backend"  
+platforms = ["linux-64"]  
+version = "0.1.0"  
+  
+# =========================  
+# Python 特性：bttoxin_digger  
+# =========================  
+[feature.python.dependencies]  
+pip = "*"  
+bttoxin_digger = ">=1.0.8,<2"  
+  
+# =========================  
+# Node 特性：Motia  
+# =========================  
+[feature.node.dependencies]  
+nodejs = "20.*"  
+pnpm = "*"
+  
+# =========================  
+# 环境定义  
+# =========================  
+[environments]  
+python = ["python"]  
+node = ["node"]  
+
+[feature.node.tasks]  
+motia-dev = "pnpm dlx motia@latest dev"
+node-ver = "node -v"  
+pnpm-ver = "pnpm -v"  
+motia-create = "pnpm dlx motia@latest create"