fix(cpa): sales bill-type whitelist for customer revenue caliber (P0)

Customer revenue/concentration now filters bill_type IN (1,4,14) (XSD/XSTHD/XSHHD).

Non-sales docs (JHD purchase, YFKD prepay, YSKD accept, QTRK, SKD, YBFYD) carry SUPPLIER unit_id and were polluting 'customer concentration' (old Top1/Top2 were our biggest suppliers; root cause of 6.04x base gap).

Unify sign filter to (sum_money+sum_tax_money)>0 (equivalent to money_only on current data, diff 0 rows) and correct the withdrawn 407-row/17.2% wording in cpa_caliber docstring.

Deriver: anchors from cpa_caliber single source; new --concentration overwrite and --only concentration (minimal 9-row write face) with pre-overwrite backup.

Tests: fixture gains bill_type/sum_tax_money; +5 whitelist cases (44 passed targeted).

backend/app/api/alert_rules.py

@@ -812,7 +812,7 @@ def run_forecast_deviation_check(
 # ============================================================
 
 def _customer_revenue_shares(db: Session, entity_id: int, lookback_months: int = 12, top_n: int = 1):
-    """聚合客户（往来单位）收入占比 — 数据源 zxt_masterbill（智享通销售单据, unit_id=客户/往来单位）
+    """聚合客户（往来单位）收入占比 — 数据源 zxt_masterbill（智享通**销售类**单据, unit_id=客户）
 
     返回 (shares, total, period_range)：
       shares = [(unit_id, amount, pct), ...] 按金额倒序取前 top_n 名
@@ -820,9 +820,17 @@ def _customer_revenue_shares(db: Session, entity_id: int, lookback_months: int =
       period_range = (start_date, end_date) ISO 字符串
     无可用数据时返回 ([], 0.0, None)。
 
-    **口径单一事实源**：SQL 已抽到 `app/utils/cpa_caliber.py`（CPA 派生器共用同一实现，
-    防「同一客户收入两份结果」）。行为与抽函数前逐字一致（同过滤、同排序、同四舍五入）。
-    用独立连接执行，避免表不存在/方言差异污染调用方 session 事务。
+    **口径单一事实源**：SQL 在 `app/utils/cpa_caliber.py`（CPA 派生器共用同一实现，
+    防「同一客户收入两份结果」）。用独立连接执行，避免表不存在/方言差异污染调用方 session 事务。
+
+    2026-10-04 P0 口径纠错（任务 finance-20261004T0905-cpa-revenue-caliber-p0）：
+      ① 增列**单据类型白名单** `bill_type IN (1,4,14)`（销售单/退货/换货）——非销售单据
+         （进货/验收/其它入库/预付款/收款/费用）的 `unit_id` 是**供应商**，混入会把
+         「客户集中度」度量成「往来单位集中度」（旧口径 Top1/Top2 恰是最大供应商）；
+      ② 取舍口径统一为 `(sum_money + sum_tax_money) > 0`（原 `money_only` 与之在本库
+         当前数据上**逐行同集、差集 0 行**，故行为**零变化**；原「17.2% 低估」表述
+         经财务复验证否，见 `cpa_caliber` 模块 docstring）。
+      预警阈值 50% 在新口径下仍不触发（Top1 22.52% < 50%）⇒ 阈值与分级不漂移。
     """
     from datetime import date, timedelta
     from app.database import get_engine
@@ -831,7 +839,7 @@ def _customer_revenue_shares(db: Session, entity_id: int, lookback_months: int =
     end = date.today()
     start = end - timedelta(days=max(1, int(lookback_months)) * 30)
     shares, total, rng = cpa_caliber.fetch_revenue_rows(
-        get_engine(), entity_id, start, end, top_n, sign_basis="money_only")
+        get_engine(), entity_id, start, end, top_n)
     if not shares:
         return ([], 0.0, None)
     return (shares, total, rng)