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/bot_bridge.py

@@ -21,7 +21,7 @@ from app.models.cost_model import StandardCost, ActualCost, AbcActivity, AbcAllo
 from app.models import KPICausality
 from app.risk_levels import risk_level
 # 裁定 R1/R5（2026-09-19 财务口径）：demo 账套任何写通道不产生业务预警；期间非规整月不入库（单一事实源）
-from app.utils.alert_entity_scope import entity_alert_guard, guard_alert_period
+from app.utils.alert_entity_scope import entity_alert_guard, guard_alert_period, month_period_clause
 from app.utils.oplog import log_op, SCOPE_GLOBAL
 import json
 
@@ -135,7 +135,8 @@ def bot_kpis(
 
     results = []
     for k in kpis:
-        latest = db.query(KPIValue).filter(KPIValue.kpi_id == k.id)\
+        latest = db.query(KPIValue).filter(
+                KPIValue.kpi_id == k.id, month_period_clause(KPIValue.period))\
             .order_by(KPIValue.period.desc()).first()
         results.append({
             "id": k.id, "name": k.kpi_name, "code": k.kpi_code,
@@ -166,7 +167,8 @@ def bot_kpi_history(
     kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
     if not kpi or kpi.entity_id != entity_id:
         raise HTTPException(404, "KPI不存在")
-    values = db.query(KPIValue).filter(KPIValue.kpi_id == kpi_id)\
+    values = db.query(KPIValue).filter(
+            KPIValue.kpi_id == kpi_id, month_period_clause(KPIValue.period))\
         .order_by(KPIValue.period.desc()).limit(limit).all()
     return {
         "kpi": {"id": kpi.id, "name": kpi.kpi_name, "code": kpi.kpi_code, "unit": kpi.unit},