docs: join the DDL statement lists in the Task 13 init command

authzMigrationSql was changed in Task 11 to return statement arrays rather
than one blob, but Task 13's init still interpolated them straight into the
migration file, which would comma-join two CREATE TABLE statements into one
unparseable line.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/plans/2026-08-04-authz-permissions-implementation.md

@@ -3212,7 +3212,10 @@ export async function runAuthzCommand(
       mkdirSync(dir, { recursive: true });
       const { up, down } = authzMigrationSql(dialect);
       const file = join(dir, `${nextMigrationNumber(dir)}_authz_tables.sql`);
-      writeFileSync(file, `-- +up\n${up}\n\n-- +down\n${down}\n`, "utf8");
+      // up/down are statement LISTS; interpolating the arrays directly would
+      // comma-join them into one unparseable statement.
+      const block = (statements: string[]) => statements.map((s) => `${s};`).join("\n\n");
+      writeFileSync(file, `-- +up\n${block(up)}\n\n-- +down\n${block(down)}\n`, "utf8");
       console.log(`Wrote ${file}`);
       console.log("Run `wrnexus db migrate` to apply it.");
       return;