docs: Add CLAUDE.md with codebase guidance

Create comprehensive documentation for future Claude Code instances working in this repository, including:
- Development commands for testing, building, and code quality
- Core architecture overview of the SQL query builder system
- Directory structure and component explanations
- Testing patterns and conventions
- Key dependencies and their purposes

🤖 Generated with [Claude Code](https://claude.ai/code)

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

exp/col.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"reflect"
 
-	"git.fsdpf.net/go/db/v2/internal/util"
+	"git.fsdpf.net/go/db/internal/util"
 )
 
 type columnList struct {
@@ -23,7 +23,8 @@ func NewColumnListExpression(vals ...interface{}) ColumnListExpression {
 		case Expression:
 			cols = append(cols, t)
 		default:
-			_, valKind := util.GetTypeInfo(val, reflect.Indirect(reflect.ValueOf(val)))
+			refVal := reflect.Indirect(reflect.ValueOf(val))
+			_, valKind := util.GetTypeInfo(val, refVal)
 
 			if valKind == reflect.Struct {
 				cm, err := util.GetColumnMap(val)
@@ -39,6 +40,12 @@ func NewColumnListExpression(vals ...interface{}) ColumnListExpression {
 					}
 					cols = append(cols, sc)
 				}
+			} else if refVal.Kind() == reflect.Slice {
+				items := make([]any, refVal.Len())
+				for i := 0; i < refVal.Len(); i++ {
+					items[i] = refVal.Index(i).Interface()
+				}
+				return NewColumnListExpression(items...)
 			} else {
 				panic(fmt.Sprintf("Cannot create expression from  %+v", val))
 			}