feat(analysis): 网页汇总表自定义列

- analyze 支持 custom_columns：白名单表达式树由服务端 Decimal 求值，
  自定义列进入汇总、分组行与明细（缺失保持不可用，不转零）
- 新增「选择网页自定义列」弹窗：从定义库（含共享）多选最多 10 列，
  应用后进入主分析表格与热力图；公式工作簿可一键导出网页已选列
- 请求去重纳入自定义列；Playwright 覆盖选择后显示与数值断言

finance/views.py

@@ -22,7 +22,7 @@ from django.utils import timezone
 from openpyxl import Workbook
 from openpyxl.cell import WriteOnlyCell
 
-from .analysis import METRICS, analyze, context, default_preferences, dimensions, scoped_facts
+from .analysis import METRICS, analyze, context, custom_columns, default_preferences, dimensions, scoped_facts
 from .importing import file_digest, profile_file, suggest_mapping, validate_mapping
 from .models import AIConfig, Audit, Dataset, Investigation, Membership, Preference, Throttle
 
@@ -521,6 +521,7 @@ def investigations(request, dataset_id):
         raise APIError("查看者不可修改调查状态", 403)
     data = body(request)
     ctx = context(ds, data.get("context", {}))
+    ctx["custom_columns"] = custom_columns(ds, data.get("context", {}))
     status, note = data.get("status"), data.get("note", "")
     if status not in ("open", "reviewing", "resolved") or not isinstance(note, str) or len(note) > 2000:
         raise APIError("调查状态或备注无效")