feat: Oracle 驱动完整化——回调体系、版本感知、驱动抽象层与测试套件

- 新增驱动抽象层 driver_adapter（go-ora/godror 双驱动切换）
- 新增 Update/Delete/Query 回调，完善 RETURNING INTO 子句
- 修复 create.go 事务悬挂行 BUG、批量 RowsAffected、主键 WHERE 注入
- 版本感知体系：分页/自增/序列默认值/BOOLEAN/32k VARCHAR2 分级能力判定
- 11g 序列+触发器自增、ON UPDATE 触发器、默认值智能转换
- 升级 go-ora v2.8.19 → v2.9.0
- 单元测试+模块测试+集成测试共 96 个，真实 Oracle 11g 全绿
- 测试 DSN 密码移除，改为 ORACLE_DSN 环境变量注入

clauses/returning_into.go

@@ -1,6 +1,7 @@
 package clauses
 
 import (
+	"fmt"
 	"gorm.io/gorm/clause"
 )
 
@@ -8,3 +9,36 @@ type ReturningInto struct {
 	Variables []clause.Column
 	Into      []*clause.Values
 }
+
+// Name returns the name of the clause
+func (r ReturningInto) Name() string {
+	return "RETURNING INTO"
+}
+
+// Build builds the SQL for the RETURNING INTO clause
+func (r ReturningInto) Build(builder clause.Builder) {
+	if len(r.Variables) > 0 {
+		builder.WriteString("RETURNING ")
+		for idx, col := range r.Variables {
+			if idx > 0 {
+				builder.WriteByte(',')
+			}
+			builder.WriteQuoted(col)
+		}
+
+		builder.WriteString(" INTO ")
+		for idx := range r.Variables {
+			if idx > 0 {
+				builder.WriteByte(',')
+			}
+			// 写入绑定变量占位符
+			builder.WriteString(fmt.Sprintf(":%d", idx+1))
+		}
+	}
+}
+
+// MergeClause merge returning into clause
+func (r ReturningInto) MergeClause(clause *clause.Clause) {
+	clause.Name = r.Name()
+	clause.Expression = r
+}