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>

jobs/bf7424dc-7147-46c8-b418-0488289a7029/task_meta.json

@@ -0,0 +1,15 @@
+{
+  "task_id": "bf7424dc-7147-46c8-b418-0488289a7029",
+  "status": "failed",
+  "current_stage": "digger",
+  "progress": 5,
+  "submission_time": "2026-01-09T09:17:23.828577",
+  "start_time": null,
+  "completion_time": null,
+  "filename": "HAN055.fna",
+  "file_size": 6099473,
+  "lang": "zh",
+  "error_message": "[Errno 2] No such file or directory",
+  "error_stage": "execution",
+  "token_hash": "0e287c9345e993bd12f6bc06f11092598760e6bd392c538bf9a3836aaa162937"
+}