feat: 预算系统6项技术改进（告警归因/实际值自动归集/真零基/派生规则/告警路径统一/现金流分类）

P1-③ 告警归因: budget_deviation_alerts+alert_type/attribution/scenario_id, 归因引擎alert_attribution.py(子KPI/科目/量价差/趋势), deviation-check统一写归因+场景, GET /deviation-alerts/{id}/attribution详情(旧告警现场组装)
P1-④ 实际值自动归集: kpi_value_sources/kpi_value_collect_logs表+CRUD+试跑+覆盖率, 采集器kpi_value_collector.py(voucher_details/进销存/cash_plans按entity+period汇总, 幂等upsert不覆盖人工), crontab每日06:30
P2-① 真零基: budget_zero_based_items逐项论证表+generate, method-comparison有论证项逐项求和is_demo=false否则fallback
P2-② 派生规则: budget_derivation_rules配置表, apply-method优先读规则rule_source=configured
P2-⑤ 告警双路径合并: deviation_engine.build_deviation_alert统一函数, 方向列表配置化kpi_alert_higher_better+alert-direction接口
P2-⑥ 现金流分类: cash_plan_classify_rules规则表+cash_plan_unclassified待分类队列, sync-cash-plans未命中进队列不静默跳过
新增: GET /kpis/{kpi_id}/values + 前端kpiApi.values(归集标签页数据源), scenario_suggestions幂等seed(init_db)
测试: test_budget_tech_improve.py 15用例, 预算相关96 passed, 全量646 passed

backend/app/database.py

@@ -97,6 +97,47 @@ def init_db():
     except Exception as e:
         logger.warning(f"user_entities初始化跳过: {e}")
 
+    # ── scenario_suggestions 告警场景建议 seed（2026-08-28 告警归因 P1-③）──
+    # 幂等：仅补缺失的 alert_type，不覆盖已有模板
+    try:
+        inspector = inspect(get_engine())
+        if "scenario_suggestions" in inspector.get_table_names():
+            Session = get_session_local()
+            session = Session()
+            try:
+                from app.models import ScenarioSuggestion
+                existing_types = {s.alert_type for s in session.query(ScenarioSuggestion).all()}
+                seeds = [
+                    dict(alert_type="cash_low", title="现金流紧张 — 加强回款催收",
+                         description="现金余额接近警戒线，建议优先处理应收款项，压缩非紧急支出。",
+                         action_template="1. 列出未来30天应收清单，逐笔催收\n2. 暂停非紧急采购/费用支出\n3. 与银行沟通短期授信额度",
+                         priority="high", sort_order=1),
+                    dict(alert_type="cash_critical", title="现金流危急 — 立即止血",
+                         description="现金余额已低于安全阈值，存在断流风险，需要立即采取止血措施。",
+                         action_template="1. 冻结一切非必要支出\n2. 高管紧急复盘资金计划\n3. 启动应收账款特别催收\n4. 评估短期融资",
+                         priority="high", sort_order=2),
+                    dict(alert_type="cost_high", title="成本超支 — 核查费用构成",
+                         description="实际成本超出预算，建议拆解到科目明细定位超支源头。",
+                         action_template="1. 查看科目明细拆解，定位超支前3科目\n2. 分析价差/量差成因（单价上涨/用量增加）\n3. 对可控费用制定压降方案",
+                         priority="medium", sort_order=3),
+                    dict(alert_type="revenue_drop", title="收入下滑 — 追量提效",
+                         description="实际收入低于预算，建议从子KPI量级分解查找差距来源。",
+                         action_template="1. 查看子KPI拆解，定位量差最大维度\n2. 分析客户/渠道/产品线缺口\n3. 制定增量获客或转化提升方案",
+                         priority="medium", sort_order=4),
+                ]
+                added = 0
+                for s in seeds:
+                    if s["alert_type"] not in existing_types:
+                        session.add(ScenarioSuggestion(**s))
+                        added += 1
+                if added:
+                    session.commit()
+                    logger.info(f"scenario_suggestions seed: 新增{added}条场景建议模板")
+            finally:
+                session.close()
+    except Exception as e:
+        logger.warning(f"scenario_suggestions seed跳过: {e}")
+
 
 def _seed_org_data(db_session):
     """插入5层级组织示例数据"""