fix(export): append semicolons to exported DDL statements

apps/desktop/src/lib/ddlExport.ts

@@ -0,0 +1,15 @@
+export function ensureSqlStatementTerminator(sql: string): string {
+  const trimmed = sql.trim();
+  if (!trimmed) return "";
+  return trimmed.endsWith(";") ? trimmed : `${trimmed};`;
+}
+
+export function buildSingleDdlExportFileContent(sql: string): string {
+  const statement = ensureSqlStatementTerminator(sql);
+  return statement ? `${statement}\n` : "";
+}
+
+export function joinExportedDdls(ddls: readonly string[]): string {
+  const statements = ddls.map(ensureSqlStatementTerminator).filter(Boolean);
+  return statements.length ? `${statements.join("\n\n")}\n` : "";
+}