improve cli logging for failed first builds during serve

packages/jaspr_cli/lib/src/commands/serve_command.dart

@@ -232,6 +232,9 @@ class ServeCommand extends BaseCommand with ProxyHelper, FlutterHelper {
       } else if (event.status == BuildStatus.failed) {
         logger.write('Failed building web assets. There is probably more output above.',
             level: Level.error, progress: ProgressState.completed);
+        if (!buildCompleter.isCompleted) {
+          buildCompleter.completeError(event);
+        }
       } else if (event.status == BuildStatus.started) {
         if (buildCompleter.isCompleted) {
           logger.write('Rebuilding web assets...', progress: ProgressState.running);
@@ -241,11 +244,16 @@ class ServeCommand extends BaseCommand with ProxyHelper, FlutterHelper {
       }
     });
 
-    await buildCompleter.future;
+    try {
+      await buildCompleter.future;
+      logger.write('Done building web assets.', progress: ProgressState.completed);
+    } on BuildResult catch (_) {
+      logger.write('Could not start dev server due to build errors.',
+          level: Level.error, progress: ProgressState.completed);
+      await shutdown();
+    }
     timer.cancel();
 
-    logger.write('Done building web assets.', progress: ProgressState.completed);
-
     return workflow;
   }
 }

packages/jaspr_cli/lib/src/logging.dart

@@ -70,7 +70,7 @@ class Logger {
     }
   }
 
-  void write(String message, {Tag tag = Tag.none, Level level = Level.info, ProgressState? progress}) {
+  void write(String message, {Tag tag = Tag.cli, Level level = Level.info, ProgressState? progress}) {
     if (level == Level.verbose && !verbose) {
       return;
     }