perf: 为库存三表/BOM/物料基础表补全高频查询列索引，防止全表扫描

inventory-backend/app/models/inbound/buy.py

@@ -13,19 +13,19 @@ class StockBuy(db.Model):
     __tablename__ = 'stock_buy'
 
     id = db.Column(db.Integer, primary_key=True)
-    base_id = db.Column(db.Integer, db.ForeignKey('material_base.id'), nullable=False)
+    base_id = db.Column(db.Integer, db.ForeignKey('material_base.id'), nullable=False, index=True)  # ★ 批量 IN 查询高频列
 
     # 身份标识
-    sku = db.Column(db.String(100))
+    sku = db.Column(db.String(100), index=True)      # ★ 条码/SKU 快速定位
     in_date = db.Column(db.DateTime)
-    barcode = db.Column(db.String(100))
+    barcode = db.Column(db.String(100), index=True)  # ★ 条码扫码查询高频列
     serial_number = db.Column(db.String(100))
     batch_number = db.Column(db.String(100))
 
     # 状态
-    status = db.Column(db.String(50), default='在库')
+    status = db.Column(db.String(50), index=True)    # ★ 在库/锁定 过滤条件
     inspection_status = db.Column(db.String(50))
-    warehouse_location = db.Column(db.String(100))
+    warehouse_location = db.Column(db.String(100), index=True)  # ★ 按库位分组/过滤
 
     # 数量
     in_quantity = db.Column(db.Numeric(19, 4), default=0)