fix: 杜邦分析period格式兼容 — 2026H1/2026-H1变体匹配，酣客ROE正常返回-12.74%

- _get_dupont_kpi支持6字符(2026H1)和7字符(2026-H1)period格式
- 之前数据库存'2026-H1'但API查'2026H1'导致读不到数据，酣客ROE返回None
- 验证：酣客ROE=-12.74%（净利率-12.74%，亏损企业正确为负）

backend/app/api/reports.py

@@ -1846,9 +1846,18 @@ def _get_dupont_kpi(db: Session, entity_id: int, kpi_code: str, period: str = "2
     ).first()
     if not kpi:
         return None
+    # 兼容period格式：数据库存"2026-H1"，查询可能传"2026H1"
+    period_variants = [period]
+    if period:
+        # "2026H1"(6字符) → 补横线 "2026-H1"
+        if len(period) == 6:
+            period_variants.append(period[:4] + "-" + period[4:])
+        # "2026-H1"(7字符) → 去横线 "2026H1"
+        elif len(period) == 7:
+            period_variants.append(period.replace("-", ""))
     v = db.query(KPIValue).filter(
         KPIValue.kpi_id == kpi.id,
-        KPIValue.period == period,
+        KPIValue.period.in_(period_variants),
         KPIValue.data_status == "verified",
     ).order_by(KPIValue.id.desc()).first()
     return v.actual_value if v else None