Add SET ROWCOUNT, SET OFFSETS, and multi-option SET parsing

Implements support for:
- SET ROWCOUNT <number|@variable>
- SET OFFSETS <options> ON/OFF with proper option sorting
- Multiple comma-separated options in PredicateSetStatement
- Multiple comma-separated options in SetStatisticsStatement

Also updates PredicateSetStatement and SetStatisticsStatement to use
string for Options field to support comma-separated values.

Enables 1 previously failing test:
- BaselinesCommon_SetOffsetsAndOnOffSetTests

Author: claude

ast/predicate_set_statement.go

@@ -1,8 +1,9 @@
 package ast
 
 // PredicateSetStatement represents a SET statement like SET ANSI_NULLS ON
+// Options can contain multiple comma-separated values like "ConcatNullYieldsNull, CursorCloseOnCommit"
 type PredicateSetStatement struct {
-	Options SetOptions
+	Options string
 	IsOn    bool
 }
 

ast/set_offsets_statement.go

@@ -0,0 +1,10 @@
+package ast
+
+// SetOffsetsStatement represents SET OFFSETS statement
+type SetOffsetsStatement struct {
+	Options string
+	IsOn    bool
+}
+
+func (s *SetOffsetsStatement) node()      {}
+func (s *SetOffsetsStatement) statement() {}

ast/set_rowcount_statement.go

@@ -0,0 +1,9 @@
+package ast
+
+// SetRowCountStatement represents SET ROWCOUNT statement
+type SetRowCountStatement struct {
+	NumberRows ScalarExpression
+}
+
+func (s *SetRowCountStatement) node()      {}
+func (s *SetRowCountStatement) statement() {}

ast/set_statistics_statement.go

@@ -1,8 +1,9 @@
 package ast
 
 // SetStatisticsStatement represents SET STATISTICS IO/PROFILE/TIME/XML statements
+// Options can contain multiple comma-separated values like "IO, Profile, Time"
 type SetStatisticsStatement struct {
-	Options SetOptions
+	Options string
 	IsOn    bool
 }
 

parser/marshal.go

@@ -226,6 +226,10 @@ func statementToJSON(stmt ast.Statement) jsonNode {
 		return predicateSetStatementToJSON(s)
 	case *ast.SetStatisticsStatement:
 		return setStatisticsStatementToJSON(s)
+	case *ast.SetRowCountStatement:
+		return setRowCountStatementToJSON(s)
+	case *ast.SetOffsetsStatement:
+		return setOffsetsStatementToJSON(s)
 	case *ast.CommitTransactionStatement:
 		return commitTransactionStatementToJSON(s)
 	case *ast.RollbackTransactionStatement:
@@ -4281,15 +4285,33 @@ func securityPrincipalToJSON(p *ast.SecurityPrincipal) jsonNode {
 func predicateSetStatementToJSON(s *ast.PredicateSetStatement) jsonNode {
 	return jsonNode{
 		"$type":   "PredicateSetStatement",
-		"Options": string(s.Options),
+		"Options": s.Options,
 		"IsOn":    s.IsOn,
 	}
 }
 
 func setStatisticsStatementToJSON(s *ast.SetStatisticsStatement) jsonNode {
 	return jsonNode{
 		"$type":   "SetStatisticsStatement",
-		"Options": string(s.Options),
+		"Options": s.Options,
+		"IsOn":    s.IsOn,
+	}
+}
+
+func setRowCountStatementToJSON(s *ast.SetRowCountStatement) jsonNode {
+	node := jsonNode{
+		"$type": "SetRowCountStatement",
+	}
+	if s.NumberRows != nil {
+		node["NumberRows"] = scalarExpressionToJSON(s.NumberRows)
+	}
+	return node
+}
+
+func setOffsetsStatementToJSON(s *ast.SetOffsetsStatement) jsonNode {
+	return jsonNode{
+		"$type":   "SetOffsetsStatement",
+		"Options": s.Options,
 		"IsOn":    s.IsOn,
 	}
 }