fix(backend): 修复日期字段解析失败导致创建单据报错

新增 model.Date 类型，支持前端传入的纯日期格式 YYYY-MM-DD：
- UnmarshalJSON 优先解析 YYYY-MM-DD，回退支持 RFC3339
- MarshalJSON 输出 YYYY-MM-DD
- Value/Scan 实现 GORM MySQL DATE 列读写
- StockInOrder/StockOutOrder/InventoryCheck 的 OrderDate/CheckDate 改用 Date 类型

feat(client): SelectionArea 全局开启文字可选中复制

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/cmd/seed/main.go

@@ -203,7 +203,7 @@ func main() {
 	}
 
 	for _, o := range inOrders {
-		order := upsertStockInOrder(db, shop.ID, wh1.ID, admin.ID, o.partnerID, o.orderNo, today.AddDate(0, 0, -3))
+		order := upsertStockInOrder(db, shop.ID, wh1.ID, admin.ID, o.partnerID, o.orderNo, model.Date{Time: today.AddDate(0, 0, -3)})
 		total := 0.0
 		for _, it := range o.items {
 			item := model.StockInItem{
@@ -231,7 +231,7 @@ func main() {
 	// ═══════════════════════════════════════════════════
 	// 出库单（已审核）→ 减库存
 	// ═══════════════════════════════════════════════════
-	outOrder := upsertStockOutOrder(db, shop.ID, wh1.ID, admin.ID, cus1.ID, "CK20260404001", today.AddDate(0, 0, -1))
+	outOrder := upsertStockOutOrder(db, shop.ID, wh1.ID, admin.ID, cus1.ID, "CK20260404001", model.Date{Time: today.AddDate(0, 0, -1)})
 	outItems := []struct {
 		prodIdx int
 		qty     float64
@@ -371,7 +371,7 @@ func upsertNumberRule(db *gorm.DB, shopID uint64, ruleType, prefix string, curre
 	}
 }
 
-func upsertStockInOrder(db *gorm.DB, shopID, whID, opID, partnerID uint64, orderNo string, date time.Time) model.StockInOrder {
+func upsertStockInOrder(db *gorm.DB, shopID, whID, opID, partnerID uint64, orderNo string, date model.Date) model.StockInOrder {
 	var o model.StockInOrder
 	if db.Where("shop_id = ? AND order_no = ?", shopID, orderNo).First(&o).Error != nil {
 		o = model.StockInOrder{
@@ -390,7 +390,7 @@ func upsertStockInOrder(db *gorm.DB, shopID, whID, opID, partnerID uint64, order
 	return o
 }
 
-func upsertStockOutOrder(db *gorm.DB, shopID, whID, opID, partnerID uint64, orderNo string, date time.Time) model.StockOutOrder {
+func upsertStockOutOrder(db *gorm.DB, shopID, whID, opID, partnerID uint64, orderNo string, date model.Date) model.StockOutOrder {
 	var o model.StockOutOrder
 	if db.Where("shop_id = ? AND order_no = ?", shopID, orderNo).First(&o).Error != nil {
 		o = model.StockOutOrder{

backend/internal/model/base.go

@@ -35,6 +35,76 @@ func (j *JSON) Scan(value interface{}) error {
 	return json.Unmarshal(bytes, j)
 }
 
+// Date 仅含日期（YYYY-MM-DD）的类型，兼容前端只传日期字符串的场景
+type Date struct{ time.Time }
+
+const dateFmt = "2006-01-02"
+
+func (d *Date) UnmarshalJSON(b []byte) error {
+	s := string(b)
+	// 去掉引号
+	if len(s) >= 2 && s[0] == '"' {
+		s = s[1 : len(s)-1]
+	}
+	if s == "" || s == "null" {
+		d.Time = time.Time{}
+		return nil
+	}
+	// 尝试纯日期格式 YYYY-MM-DD
+	if t, err := time.ParseInLocation(dateFmt, s, time.Local); err == nil {
+		d.Time = t
+		return nil
+	}
+	// 回退：标准 RFC3339
+	t, err := time.Parse(time.RFC3339, s)
+	if err != nil {
+		return fmt.Errorf("cannot parse date %q", s)
+	}
+	d.Time = t
+	return nil
+}
+
+func (d Date) MarshalJSON() ([]byte, error) {
+	if d.Time.IsZero() {
+		return []byte(`""`), nil
+	}
+	return []byte(`"` + d.Time.Format(dateFmt) + `"`), nil
+}
+
+// Value / Scan 让 GORM 正确读写 MySQL DATE 列
+func (d Date) Value() (driver.Value, error) {
+	if d.Time.IsZero() {
+		return nil, nil
+	}
+	return d.Time.Format(dateFmt), nil
+}
+
+func (d *Date) Scan(value interface{}) error {
+	if value == nil {
+		d.Time = time.Time{}
+		return nil
+	}
+	switch v := value.(type) {
+	case time.Time:
+		d.Time = v
+	case []byte:
+		t, err := time.ParseInLocation(dateFmt, string(v), time.Local)
+		if err != nil {
+			return err
+		}
+		d.Time = t
+	case string:
+		t, err := time.ParseInLocation(dateFmt, v, time.Local)
+		if err != nil {
+			return err
+		}
+		d.Time = t
+	default:
+		return fmt.Errorf("cannot scan type %T into Date", value)
+	}
+	return nil
+}
+
 // Base 公共字段
 type Base struct {
 	ID        uint64     `gorm:"primaryKey;autoIncrement" json:"id"`

backend/internal/model/stock.go

@@ -13,7 +13,7 @@ type StockInOrder struct {
 	OperatorID   uint64     `gorm:"not null" json:"operator_id"`
 	ReviewerID   *uint64    `json:"reviewer_id"`
 	Status       string     `gorm:"type:enum('draft','pending','approved','rejected');default:'draft'" json:"status"`
-	OrderDate    time.Time  `gorm:"type:date" json:"order_date"`
+	OrderDate    Date       `gorm:"type:date" json:"order_date"`
 	TotalAmount  float64    `gorm:"type:decimal(16,2);default:0" json:"total_amount"`
 	ReviewedAt   *time.Time `json:"reviewed_at"`
 	CustomFields JSON       `gorm:"type:json" json:"custom_fields,omitempty"`
@@ -51,7 +51,7 @@ type StockOutOrder struct {
 	OperatorID   uint64     `gorm:"not null" json:"operator_id"`
 	ReviewerID   *uint64    `json:"reviewer_id"`
 	Status       string     `gorm:"type:enum('draft','pending','approved','rejected');default:'draft'" json:"status"`
-	OrderDate    time.Time  `gorm:"type:date" json:"order_date"`
+	OrderDate    Date       `gorm:"type:date" json:"order_date"`
 	TotalAmount  float64    `gorm:"type:decimal(16,2);default:0" json:"total_amount"`
 	ReviewedAt   *time.Time `json:"reviewed_at"`
 	CustomFields JSON       `gorm:"type:json" json:"custom_fields,omitempty"`
@@ -116,7 +116,7 @@ type InventoryCheck struct {
 	WarehouseID uint64    `gorm:"not null" json:"warehouse_id"`
 	OperatorID  uint64    `gorm:"not null" json:"operator_id"`
 	Status      string    `gorm:"type:enum('draft','completed');default:'draft'" json:"status"`
-	CheckDate   time.Time `gorm:"type:date" json:"check_date"`
+	CheckDate   Date      `gorm:"type:date" json:"check_date"`
 	Remark      string    `gorm:"size:500" json:"remark"`
 
 	Items []InventoryCheckItem `gorm:"foreignKey:CheckID" json:"items,omitempty"`

client/lib/main.dart

@@ -80,6 +80,7 @@ class _RouterApp extends ConsumerWidget {
       theme: AppTheme.light(),
       routerConfig: router,
       debugShowCheckedModeBanner: false,
+      builder: (context, child) => SelectionArea(child: child!),
     );
   }
 }