fix(cma): entity isolation batch4 (cash plan writes, budget ownership, read leaks, okr template)

P0-A cash.py: scope api_update_plan / api_delete_plan / api_complete_plan /
api_register_payment to session entity (cross-entity id -> 404, aligning with
the file's existing get_entity_id endpoints).
P0-B budget.py: write entity_id on BudgetPlan creation + require the KPI to
belong to the session entity; scope /comparison, /comparison/kpi/{id} and
/deviation-report reads to the session entity.
P1 notifications.py: explicit field whitelist (name/config/enabled) on
update_channel to close mass-assignment.
P1 read leaks scoped to session entity: bot_kpis list, data_quality check/stats
(KPI calibre only; quality-log table has no entity_id column), kpis causality
chain + associate-map (KPI and map ownership), dashboard my-kpis,
customer_dashboard list, kpi_governance audit, budget_generate candidates,
driver_budget history (+ entity_id on its write path), expenses stats
(+ entity_id on its write path).
P2 okr_templates.py: write entity_id on the StrategicMap created by apply.

tests: tests/test_cross_entity_isolation_batch4_20260921.py (30 cases;
RED before fix = 22 failed, GREEN after = 30 passed; full suite 1302 passed /
1 xfailed / 0 failed).

backend/app/api/customer_dashboard.py

@@ -5,6 +5,7 @@ from sqlalchemy import func, desc
 from typing import Optional
 from datetime import datetime, timedelta
 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
 import logging
@@ -45,6 +46,7 @@ def list_customer_kpis(
     end_date: str = Query(None),
     db: Session = Depends(get_db),
     current_user: User = Depends(require_auth),
+    entity_id: int = Depends(get_entity_id),
 ):
     """获取客户维度KPI列表（含最新值、预警、趋势）"""
     start, end = parse_period(period, start_date, end_date)
@@ -54,6 +56,7 @@ def list_customer_kpis(
     kpis = db.query(KPIDefinition).filter(
         KPIDefinition.status == "active",
         KPIDefinition.dimension == "customer",
+        KPIDefinition.entity_id == entity_id,  # 账套隔离 2026-09-21
     ).order_by(KPIDefinition.kpi_code).all()
 
     result = []