fix(fetch-caliber): 取数层排除半年/预测伪期间 + subjects 响应补 entity_id

R3 期间口径（仅 YYYY-MM）延伸到取数层：新增 alert_entity_scope.month_period_clause()（跨库可移植 SQL 等价式），应用到 15 个文件 26 处「按 period 倒序取最新值/最近N期」位点；dashboard 原 MySQL-only REGEXP 正则收口到同单一事实源。

GET /api/cma/subjects 响应增补 entity_id（NULL=全局标准准则科目 / N=账套私有明细），既有 10 字段语义与名称不变。

证据：pending-tasks/_reports/yanxue-20260924-cma-fetch-caliber-fixes-fullstack.md（改前/改后 A/B：F_NET_PROFIT 2026-H2/-55.0 → 2026-08/-10.46）。新增 7 例回归测试；全量 1 failed(预存在) 1473 passed，基线同项。

backend/app/api/customer_dashboard.py

@@ -8,6 +8,7 @@ from app.database import get_db
 from app.deps import get_entity_id
 from app.auth_middleware import require_auth, require_role
 from app.models import KPIDefinition, KPIValue, KPIAlert, User
+from app.utils.alert_entity_scope import month_period_clause
 import logging
 
 logger = logging.getLogger("cma.customer")
@@ -86,7 +87,7 @@ def list_customer_kpis(
             latest_val = sum(v.actual_value for v in values if v.actual_value) if values else None
             latest = type('obj', (object,), {"actual_value": latest_val, "period": f"{start_date}~{end_date}"})() if latest_val else None
         else:
-            latest = base_query.order_by(KPIValue.period.desc()).first()
+            latest = base_query.filter(month_period_clause(KPIValue.period)).order_by(KPIValue.period.desc()).first()
 
         # 最新预警
         alert = db.query(KPIAlert).filter(
@@ -127,6 +128,7 @@ def list_customer_kpis(
         # 最近6期趋势数据
         period_q = db.query(KPIValue).filter(
             KPIValue.kpi_id == k.id,
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).limit(6).all()
         period_values = [
             {"period": v.period, "value": v.actual_value}
@@ -171,6 +173,7 @@ def get_kpi_trend(
     # 获取最近N期数据
     values = db.query(KPIValue).filter(
         KPIValue.kpi_id == kpi_id,
+        month_period_clause(KPIValue.period),
     ).order_by(KPIValue.period.desc()).limit(months).all()
 
     trend_data = [