feat: 初始化核心数据库表结构、Go模型并包含日期字段类型迁移脚本

internal/models/models.go

@@ -348,7 +348,7 @@ type Transaction struct {
 	CategoryID      uint            `gorm:"not null;index" json:"category_id"`
 	AccountID       uint            `gorm:"not null;index" json:"account_id"`
 	Currency        Currency        `gorm:"size:10;not null;default:'CNY'" json:"currency"`
-	TransactionDate time.Time       `gorm:"type:date;not null;index" json:"transaction_date"`
+	TransactionDate time.Time       `gorm:"type:datetime;not null;index" json:"transaction_date"`
 	Note            string          `gorm:"size:500" json:"note,omitempty"`
 	ImagePath       string          `gorm:"size:255" json:"image_path,omitempty"`
 	RecurringID     *uint           `gorm:"index" json:"recurring_id,omitempty"`
@@ -361,9 +361,8 @@ type Transaction struct {
 	// Validates: Requirements 3.10
 	LedgerID *uint `gorm:"index" json:"ledger_id,omitempty"`
 
-	// Precise time recording
-	// Feature: accounting-feature-upgrade
-	// Validates: Requirements 5.2
+	// TransactionTime is deprecated - time is now stored in TransactionDate (DATETIME)
+	// Kept for backward compatibility with existing data
 	TransactionTime *time.Time `gorm:"type:time" json:"transaction_time,omitempty"`
 
 	// Transaction sub-type for special transactions