feat: 完善扫描器、exec 及 schema 相关功能

- exec/scanner: 用 *interface{} 替换 **json.RawMessage 扫描目标，兼容 DuckDB 返回 map[string]interface{} 的场景；新增 toJSONRawMessage 转换函数
- exec/scanner: ScanVal 支持结构体指针，通过 JSON 中间层转换（DuckDB STRUCT 列）
- exec/scanner: 将 *sql.RawBytes 和 *[]byte 的处理从 ScanValContext 移入 scanner.ScanVal
- exec/query_executor: 简化 ScanValContext，移除私有 scan 方法
- exec: 补充 scanner 级别 ScanVal 测试用例
- internal/util/reflect: 重写 SafeSetVarValue，修复非指针 src 及 nil 指针字段的 panic
- internal/util/column_map: 恢复非匿名带标签结构体字段的展开逻辑
- schema: 新增 vector 列类型支持
- engine: 补充 DuckDB 相关配置
- dialect/sqlite3/vtab: 完善虚拟表适配器
- 各方言测试改用 sqlmock 虚拟连接

exec/scanner_internal_test.go

@@ -1,9 +1,10 @@
 package exec
 
 import (
+	"database/sql"
+	"encoding/json"
 	"testing"
 
-	"git.fsdpf.net/go/db/exp"
 	"github.com/DATA-DOG/go-sqlmock"
 	"github.com/stretchr/testify/suite"
 )
@@ -81,14 +82,162 @@ func (s *scannerSuite) TestGetRecords() {
 				AddRow("111 Test Addr", "Test1"),
 		)
 
-	rows, err := db.Query("SELECT \\* FROM `items`")
+	rows, err := db.Query("SELECT * FROM `items`")
 	s.Require().NoError(err)
 
 	result, err := NewScanner(rows).GetRecords()
 	s.Require().NoError(err)
 
-	s.Equal([]exp.Record{
+	s.Equal([]map[string]any{
 		{"address": "111 Test Addr", "name": "Test1"},
 		{"address": "111 Test Addr", "name": "Test1"},
 	}, result)
 }
+
+func (s *scannerSuite) TestScanVal() {
+	db, mock, err := sqlmock.New()
+	s.Require().NoError(err)
+
+	mock.ExpectQuery(`SELECT "id" FROM "items"`).
+		WillReturnRows(sqlmock.NewRows([]string{"id"}).AddRow(42))
+
+	rows, err := db.Query(`SELECT "id" FROM "items"`)
+	s.Require().NoError(err)
+
+	sc := NewScanner(rows)
+	s.True(sc.Next())
+
+	var id int64
+	err = sc.ScanVal(&id)
+	s.Require().NoError(err)
+	s.Equal(int64(42), id)
+}
+
+func (s *scannerSuite) TestScanVal_withRawBytes() {
+	db, mock, err := sqlmock.New()
+	s.Require().NoError(err)
+
+	mock.ExpectQuery(`SELECT "data" FROM "items"`).
+		WillReturnRows(sqlmock.NewRows([]string{"data"}).AddRow([]byte(testByteSliceContent)))
+
+	rows, err := db.Query(`SELECT "data" FROM "items"`)
+	s.Require().NoError(err)
+
+	sc := NewScanner(rows)
+	s.True(sc.Next())
+
+	var rb sql.RawBytes
+	err = sc.ScanVal(&rb)
+	s.Require().NoError(err)
+
+	_ = sc.Close()
+	// 关闭后缓冲区应已拷贝，值仍然有效
+	s.Equal(sql.RawBytes(testByteSliceContent), rb)
+}
+
+func (s *scannerSuite) TestScanVal_withByteSlice() {
+	db, mock, err := sqlmock.New()
+	s.Require().NoError(err)
+
+	mock.ExpectQuery(`SELECT "data" FROM "items"`).
+		WillReturnRows(sqlmock.NewRows([]string{"data"}).AddRow(testByteSliceContent))
+
+	rows, err := db.Query(`SELECT "data" FROM "items"`)
+	s.Require().NoError(err)
+
+	sc := NewScanner(rows)
+	s.True(sc.Next())
+
+	var b []byte
+	err = sc.ScanVal(&b)
+	s.Require().NoError(err)
+	s.Equal([]byte(testByteSliceContent), b)
+}
+
+func (s *scannerSuite) TestScanVal_withByteSlice_complexJSON() {
+	db, mock, err := sqlmock.New(sqlmock.ValueConverterOption(anyValueConverter{}))
+	s.Require().NoError(err)
+
+	payload := map[string]interface{}{"key": "val", "num": float64(1)}
+	mock.ExpectQuery(`SELECT "data" FROM "items"`).
+		WillReturnRows(mock.NewRows([]string{"data"}).AddRow(payload))
+
+	rows, err := db.Query(`SELECT "data" FROM "items"`)
+	s.Require().NoError(err)
+
+	sc := NewScanner(rows)
+	s.True(sc.Next())
+
+	var b []byte
+	err = sc.ScanVal(&b)
+	s.Require().NoError(err)
+
+	var got map[string]interface{}
+	s.Require().NoError(json.Unmarshal(b, &got))
+	s.Equal(payload, got)
+}
+
+func (s *scannerSuite) TestScanVal_withStruct() {
+	type DocItem struct {
+		Title string `json:"title"`
+		Score int    `json:"score"`
+	}
+	db, mock, err := sqlmock.New(sqlmock.ValueConverterOption(anyValueConverter{}))
+	s.Require().NoError(err)
+
+	mock.ExpectQuery(`SELECT "doc" FROM "items"`).
+		WillReturnRows(mock.NewRows([]string{"doc"}).
+			AddRow(map[string]interface{}{"title": "hello", "score": float64(99)}))
+
+	rows, err := db.Query(`SELECT "doc" FROM "items"`)
+	s.Require().NoError(err)
+
+	sc := NewScanner(rows)
+	s.True(sc.Next())
+
+	var doc DocItem
+	err = sc.ScanVal(&doc)
+	s.Require().NoError(err)
+	s.Equal(DocItem{Title: "hello", Score: 99}, doc)
+}
+
+func (s *scannerSuite) TestScanVal_withStruct_null() {
+	type DocItem struct {
+		Title string `json:"title"`
+	}
+	db, mock, err := sqlmock.New()
+	s.Require().NoError(err)
+
+	mock.ExpectQuery(`SELECT "doc" FROM "items"`).
+		WillReturnRows(sqlmock.NewRows([]string{"doc"}).AddRow(nil))
+
+	rows, err := db.Query(`SELECT "doc" FROM "items"`)
+	s.Require().NoError(err)
+
+	sc := NewScanner(rows)
+	s.True(sc.Next())
+
+	var doc DocItem
+	err = sc.ScanVal(&doc)
+	s.Require().NoError(err)
+	s.Equal(DocItem{}, doc)
+}
+
+func (s *scannerSuite) TestScanVal_withStruct_sqlScanner() {
+	db, mock, err := sqlmock.New()
+	s.Require().NoError(err)
+
+	mock.ExpectQuery(`SELECT "name" FROM "items"`).
+		WillReturnRows(sqlmock.NewRows([]string{"name"}).AddRow("hello"))
+
+	rows, err := db.Query(`SELECT "name" FROM "items"`)
+	s.Require().NoError(err)
+
+	sc := NewScanner(rows)
+	s.True(sc.Next())
+
+	var ns sql.NullString
+	err = sc.ScanVal(&ns)
+	s.Require().NoError(err)
+	s.Equal(sql.NullString{String: "hello", Valid: true}, ns)
+}