Add Prisma 7 flag support

pkg/writers/writer.go

@@ -51,6 +51,9 @@ type WriterOptions struct {
 	//   "stdlib"                — database/sql (sql.NullString, sql.NullInt32, …)
 	NullableTypes string
 
+	// Prisma7 enables Prisma 7-specific output for Prisma writers.
+	Prisma7 bool
+
 	// Additional options can be added here as needed
 	Metadata map[string]interface{}
 }