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/bttoxin_shoter.py

@@ -397,7 +397,7 @@ def compute_similarity_weight(identity: float, coverage: float, hmm: bool) -> fl
 
 
 def parse_all_toxins(tsv_path: Path) -> pd.DataFrame:
-    df = pd.read_csv(tsv_path, sep="\t", dtype=str, low_memory=False)
+    df = pd.read_csv(tsv_path, sep="\t", dtype=str, engine="python")
     # Coerce needed fields
     for col in ["Identity", "Aln_length", "Hit_length"]:
         df[col] = pd.to_numeric(df[col], errors="coerce")
@@ -658,7 +658,13 @@ def main():
                 d = index.orders_for_name_or_backoff(fam)
             return bool(d)
         df = df[df.apply(_has_index_orders, axis=1)]
-    strains = sorted(df["Strain"].astype(str).unique().tolist())
+
+    # Handle empty DataFrame - preserve columns and create empty outputs
+    if df.shape[0] == 0:
+        print("[Shotter] No hits passed filters, creating empty output files")
+        strains: List[str] = []
+    else:
+        strains = sorted(df["Strain"].astype(str).unique().tolist())
 
     all_hits: List[ToxinHit] = []
     all_strain_scores: List[StrainScores] = []