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>

scripts/run_single_fna_pipeline.py

@@ -46,6 +46,8 @@ from pathlib import Path
 from typing import Dict, Any, List
 
 # Import PixiRunner and command builders from scripts
+# Add scripts directory to path for pixi_runner import
+sys.path.insert(0, str(Path(__file__).parent))
 from pixi_runner import PixiRunner, build_shotter_command, build_plot_command