Test builds: tool/dev_release.sh builds Linux here and publishes to a dev prerelease that dev builds update from

X.Y.Z-dev.N builds read the dev prerelease's manifest as well as the
stable one and take the newer, so a tester gets each test build through
the normal update and lands back on stable at the release.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/lib/src/update/update_controller.dart

@@ -107,7 +107,8 @@ class UpdateController {
     final root = _root;
     if (root != null) await cleanupUpdateLeftovers(root);
     try {
-      final m = await fetchManifest(url: manifestUrl);
+      final m = await fetchLatestManifest(
+          currentVersion: currentVersion, url: manifestUrl);
       if (!isNewerVersion(currentVersion, m.version)) {
         _log.info('up to date ($currentVersion, latest ${m.version})');
         lastCheck.value = 'Up to date';