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/api/zero_based.py

@@ -0,0 +1,217 @@
+"""零基预算逐项论证 API — 管理会计OS (P2-① 2026-08-28)
+
+CRUD 逐项论证项(budget_zero_based_items) + generate 生成零基预算写 budget_plans。
+method-comparison 的 zero_based 分支优先读论证项（有数据→逐项求和 is_demo=false）。
+"""
+from fastapi import APIRouter, Depends, HTTPException, Query
+from sqlalchemy.orm import Session
+from typing import Optional
+from datetime import datetime
+
+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 BudgetZeroBasedItem, KPIDefinition, BudgetPlan
+
+router = APIRouter(
+    prefix="/api/cma/budget",
+    tags=["零基预算"],
+    dependencies=[Depends(require_role("ceo", "finance", "it"))],
+)
+
+
+@router.get("/zero-based/items")
+def list_zero_based_items(
+    kpi_id: Optional[int] = Query(None),
+    period: Optional[str] = Query(None),
+    db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id),
+):
+    """零基逐项论证列表（kpi_id+period 过滤）"""
+    query = db.query(BudgetZeroBasedItem).filter(BudgetZeroBasedItem.entity_id == entity_id)
+    if kpi_id:
+        query = query.filter(BudgetZeroBasedItem.kpi_id == kpi_id)
+    if period:
+        query = query.filter(BudgetZeroBasedItem.period == period)
+    rows = query.order_by(BudgetZeroBasedItem.id.desc()).all()
+
+    kpi_ids = {r.kpi_id for r in rows}
+    kpis = {k.id: k for k in db.query(KPIDefinition).filter(KPIDefinition.id.in_(kpi_ids)).all()} if kpi_ids else {}
+    result = []
+    for r in rows:
+        kpi = kpis.get(r.kpi_id)
+        result.append({
+            "id": r.id,
+            "kpi_id": r.kpi_id,
+            "kpi_code": kpi.kpi_code if kpi else "",
+            "kpi_name": kpi.kpi_name if kpi else "",
+            "period": r.period,
+            "item_name": r.item_name,
+            "item_category": r.item_category,
+            "base_value": r.base_value,
+            "justification": r.justification,
+            "proposed_value": r.proposed_value,
+            "status": r.status,
+            "created_by": r.created_by,
+            "created_at": r.created_at.isoformat() if r.created_at else None,
+        })
+    total_proposed = round(sum(r.proposed_value for r in rows), 2)
+    return {"data": result, "total": len(result), "total_proposed": total_proposed}
+
+
+@router.post("/zero-based/items")
+def create_zero_based_item(
+    data: dict,
+    db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id),
+    current_user=Depends(require_auth),
+):
+    """新建逐项论证项"""
+    kpi_id = data.get("kpi_id")
+    period = data.get("period")
+    item_name = data.get("item_name")
+    base_value = data.get("base_value")
+    proposed_value = data.get("proposed_value")
+    if not kpi_id or not period or not item_name:
+        raise HTTPException(400, "缺少必要参数: kpi_id, period, item_name")
+    if base_value is None:
+        base_value = 0
+    if proposed_value is None:
+        proposed_value = 0
+
+    kpi = db.query(KPIDefinition).filter(
+        KPIDefinition.id == kpi_id,
+        KPIDefinition.entity_id == entity_id,
+    ).first()
+    if not kpi:
+        raise HTTPException(404, "KPI不存在")
+
+    row = BudgetZeroBasedItem(
+        entity_id=entity_id,
+        kpi_id=kpi_id,
+        period=period,
+        item_name=item_name,
+        item_category=data.get("item_category", "discretionary"),
+        base_value=base_value,
+        justification=data.get("justification"),
+        proposed_value=proposed_value,
+        status=data.get("status", "draft"),
+        created_by=data.get("created_by") or (current_user.name if hasattr(current_user, "name") else None),
+    )
+    db.add(row)
+    db.commit()
+    db.refresh(row)
+    return {"message": "论证项已创建", "id": row.id}
+
+
+@router.put("/zero-based/items/{item_id}")
+def update_zero_based_item(
+    item_id: int,
+    data: dict,
+    db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id),
+    current_user=Depends(require_auth),
+):
+    """更新逐项论证项"""
+    row = db.query(BudgetZeroBasedItem).filter(
+        BudgetZeroBasedItem.id == item_id,
+        BudgetZeroBasedItem.entity_id == entity_id,
+    ).first()
+    if not row:
+        raise HTTPException(404, "论证项不存在")
+    for field in ("item_name", "item_category", "base_value", "justification",
+                  "proposed_value", "status"):
+        if field in data:
+            setattr(row, field, data[field])
+    db.commit()
+    return {"message": "论证项已更新", "id": row.id}
+
+
+@router.delete("/zero-based/items/{item_id}")
+def delete_zero_based_item(
+    item_id: int,
+    db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id),
+    current_user=Depends(require_auth),
+):
+    """删除逐项论证项"""
+    row = db.query(BudgetZeroBasedItem).filter(
+        BudgetZeroBasedItem.id == item_id,
+        BudgetZeroBasedItem.entity_id == entity_id,
+    ).first()
+    if not row:
+        raise HTTPException(404, "论证项不存在")
+    db.delete(row)
+    db.commit()
+    return {"message": "论证项已删除"}
+
+
+@router.post("/zero-based/generate")
+def generate_zero_based_budget(
+    data: dict,
+    db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id),
+    current_user=Depends(require_auth),
+):
+    """生成零基预算 = Σ(proposed_value)，写 budget_plans（version='zbb-YYYYMMDD'，calc_logic='zero_based_itemized'）"""
+    kpi_id = data.get("kpi_id")
+    period = data.get("period")
+    year = data.get("year")
+    if not kpi_id or not period:
+        raise HTTPException(400, "缺少必要参数: kpi_id, period")
+
+    items = db.query(BudgetZeroBasedItem).filter(
+        BudgetZeroBasedItem.entity_id == entity_id,
+        BudgetZeroBasedItem.kpi_id == kpi_id,
+        BudgetZeroBasedItem.period == period,
+    ).all()
+    if not items:
+        raise HTTPException(400, f"期间 {period} 无逐项论证项，请先录入")
+
+    total = round(sum(i.proposed_value for i in items), 2)
+    # 解析年份
+    if not year:
+        try:
+            year = int(period.split("-")[0])
+        except Exception:
+            year = datetime.now().year
+    month = 0
+    try:
+        month = int(period.split("-")[1]) if "-" in period else 0
+    except Exception:
+        month = 0
+
+    version = f"zbb-{datetime.now().strftime('%Y%m%d')}"
+    # 删除同KPI同期间同版本旧预算，防重复
+    db.query(BudgetPlan).filter(
+        BudgetPlan.entity_id == entity_id,
+        BudgetPlan.kpi_id == kpi_id,
+        BudgetPlan.period == period,
+        BudgetPlan.version == version,
+    ).delete()
+
+    bp = BudgetPlan(
+        entity_id=entity_id,
+        kpi_id=kpi_id,
+        period=period,
+        budget_value=total,
+        budget_year=year,
+        budget_month=month,
+        version=version,
+        status="active",
+        source_type="zero_based",
+        calc_logic="zero_based_itemized",
+        remark=f"零基逐项论证生成: {len(items)}项 Σ(proposed_value)={total}",
+    )
+    db.add(bp)
+    db.commit()
+
+    return {
+        "message": f"零基预算已生成: {total}（{len(items)}项论证）",
+        "kpi_id": kpi_id,
+        "period": period,
+        "total": total,
+        "item_count": len(items),
+        "version": version,
+        "plan_id": bp.id,
+    }