Await what the transactions start (PostgreSQL pass follow-up): a project export ran detached: the viewer callback returned buildExport()'s promise without awaiting it, so the route answered before the archive existed. A sync callback that calls async code returns before the work is done, so writes could land outside or after their transaction. npm test 28/28.

ddiff --git a/server/http/portal.js b/server/http/portal.js
iindex f441488..81feaf1 100644
---- a/server/http/portal.js
++++ b/server/http/portal.js
@@@ -243,7 +243,7 @@ ${canChange || self ? html`<form method="post" action="/projects/${project.id}/m
      r.get('/:project/export', idParams, B('codes.project.export'), async (req, res) => {
          const project = await loadProject(req, res);
          if (!project) return;
--        const got = await net(req, res, (t) => buildExport({
++        const got = await net(req, res, async (t) => await buildExport({
              network, token: t, project, includeAudit: atLeast(project.role, 'admin') || req.viewer.staff, releases, playground, trust,
              meta: { now: new Date().toISOString(), subject: req.viewer.subject, networkUrl: config.networkUrl, baseUrl: config.baseUrl },
          }));
@@@ -264,7 +264,7 @@ ${canChange || self ? html`<form method="post" action="/projects/${project.id}/m
          exporting.add(project.id);
          try {
              const meta = { now: new Date().toISOString(), subject: req.viewer.subject, networkUrl: config.networkUrl, baseUrl: config.baseUrl };
--            const metadata = await net(req, res, (t) => buildExport({ network, token: t, project, includeAudit: true, releases, playground, trust, meta }));
++            const metadata = await net(req, res, async (t) => await buildExport({ network, token: t, project, includeAudit: true, releases, playground, trust, meta }));
              if (!metadata.ok) return problemPage(req, res, metadata.problem, { title: 'Export', back: back(req) });
              const mintToken = async (audience, env) => {
                  const got = await net(req, res, (t) => network.projects.exportToken(t, project.id, { audience, env }));