feat(validation): enforce single-anchor fragments

- skip fused/shared/multi-anchor side systems during extraction
- add fragment library schema and fragment_library.csv export
- make scaffold prep strict for non-spliceable positions

README.md

@@ -96,6 +96,7 @@ pixi run python scripts/validate_macrolactone_db.py \
 validation_output/
 ├── README.md                    # 目录说明
 ├── fragments.db                 # SQLite 数据库
+├── fragment_library.csv         # 最终片段库导出（含 has_dummy_atom / splice_ready）
 ├── summary.csv                  # 汇总表（含 ml_id, chembl_id）
 ├── summary_statistics.json      # 统计信息
 ├── ring_size_12/                # 按环大小组织
@@ -124,11 +125,15 @@ sqlite3 validation_output/fragments.db \
    FROM parent_molecules \
    WHERE classification='standard_macrolactone' LIMIT 5;"
 
+# 查询最终片段库
+sqlite3 validation_output/fragments.db \
+  "SELECT source_type, source_parent_ml_id, cleavage_position, has_dummy_atom, splice_ready \
+   FROM fragment_library_entries LIMIT 10;"
+
 # 查询片段
 sqlite3 validation_output/fragments.db \
-  "SELECT fragment_id, cleavage_position, dummy_isotope \
-   FROM side_chain_fragments \
-   WHERE ml_id='ML00000001';"
+  "SELECT fragment_id, cleavage_position, dummy_isotope, has_dummy_atom, dummy_atom_count \
+   FROM side_chain_fragments LIMIT 10;"
 
 # 按环大小统计
 sqlite3 validation_output/fragments.db \
@@ -144,6 +149,8 @@ sqlite3 validation_output/fragments.db \
 | `classification` | standard_macrolactone / non_standard_macrocycle / not_macrolactone |
 | `dummy_isotope` | 裂解位置编号，用于片段重建 |
 | `cleavage_position` | 环上的断裂位置 |
+| `has_dummy_atom` | 该片段是否带 dummy 原子，可用于区分可直接拼接片段 |
+| `splice_ready` | 是否与当前单锚点拼接流程直接兼容 |
 
 ## Legacy Scripts