Add support for TRUNCATE TEMPORARY TABLE syntax

Parse TEMPORARY keyword in TRUNCATE statements and skip it when
determining the table name.

Fixed test: 00670_truncate_temporary_table/stmt7

Author: claude

ast/ast.go

@@ -692,6 +692,7 @@ const (
 // TruncateQuery represents a TRUNCATE statement.
 type TruncateQuery struct {
 	Position  token.Position `json:"-"`
+	Temporary bool           `json:"temporary,omitempty"`
 	IfExists  bool           `json:"if_exists,omitempty"`
 	Database  string         `json:"database,omitempty"`
 	Table     string         `json:"table"`

parser/parser.go

@@ -5849,6 +5849,12 @@ func (p *Parser) parseTruncate() *ast.TruncateQuery {
 
 	p.nextToken() // skip TRUNCATE
 
+	// Handle TEMPORARY keyword
+	if p.currentIs(token.TEMPORARY) {
+		trunc.Temporary = true
+		p.nextToken()
+	}
+
 	if p.currentIs(token.TABLE) {
 		p.nextToken()
 	}

parser/testdata/00670_truncate_temporary_table/metadata.json

@@ -1,5 +1 @@
-{
-  "explain_todo": {
-    "stmt7": true
-  }
-}
+{}