test(cma): clear 10 pre-existing baseline failures (cma-baseline-tests-cleanup-20260915)

No production code changed. Root causes were all test-side staleness:

- test_cash TestVoucherImport: fixture filename contained 'test' -> rejected by the intentional import guard (d71c7fe); renamed, and missing-columns case now asserts the column check is what returns 400

- test_budget_tech_improve TestP1ValueCollect: seeded voucher_details source rows; collector deliberately skips empty aggregates since d71c7fe (no more implicit 0), and preview call now passes an explicit period

- test_roadmap_r2r5 / test_budget / test_ai_suggestions: seeds hardcoded 2026-08 (authoring month) while detectors/rule engine use the current month -> replaced with current-period seeds

pytest tests/ -q -rf: 1094 passed, 1 xfailed, 0 failed (baseline was 10 failed, 1084 passed, 1 xfailed)

backend/tests/test_budget.py

@@ -3,6 +3,7 @@ import pytest
 from fastapi.testclient import TestClient
 from sqlalchemy.orm import Session
 from tests.conftest import create_test_user, get_token_for_user, auth_header, create_test_kpi
+from datetime import datetime
 from app.models.budget_plan import BudgetPlan
 from app.models import KPIValue, SystemConfig, CashPlan
 
@@ -341,14 +342,21 @@ class TestBudgetRollForward:
         data = resp.json()
         assert "滚动预算已延展" in data["message"]
         assert len(data["rolled_kpis"]) == 1
-        # 新增月份 = 当前月(08) + 12 = 明年08
-        assert data["rolled_kpis"][0]["added_period"].startswith("2027-")
+        # 新增月份 = 当前月 + rolling_months(12)（实现口径见 budget.py:budget_roll_forward）
+        # 用例原写死 2026-08+12=2027-08，跨月后与实现错配（2026-09 跨月实证）
+        now = datetime.now()
+        exp_year, exp_month = now.year, now.month + 12
+        while exp_month > 12:
+            exp_month -= 12
+            exp_year += 1
+        expected_period = f"{exp_year}-{exp_month:02d}"
+        assert data["rolled_kpis"][0]["added_period"] == expected_period
 
         # 最早月(2026-01)被删除
         from app.models import BudgetPlan as BP
         periods = [p.period for p in db.query(BP).filter(BP.kpi_id == kpi.id).all()]
         assert "2026-01" not in periods
-        assert "2027-08" in periods
+        assert expected_period in periods
 
 
 class TestBudgetComparison: