Guard notifications job when table missing

Services/VigenciaNotificationBackgroundService.cs

@@ -42,6 +42,12 @@ public class VigenciaNotificationBackgroundService : BackgroundService
             using var scope = _scopeFactory.CreateScope();
             var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
 
+            if (!await TableExistsAsync(db, "Notifications", stoppingToken))
+            {
+                _logger.LogWarning("Tabela Notifications ainda não existe. Aguardando migrations.");
+                return;
+            }
+
             var today = DateTime.UtcNow.Date;
             var reminderDays = _options.ReminderDays
                 .Distinct()
@@ -159,6 +165,30 @@ public class VigenciaNotificationBackgroundService : BackgroundService
         }
     }
 
+    private static async Task<bool> TableExistsAsync(AppDbContext db, string tableName, CancellationToken stoppingToken)
+    {
+        if (!db.Database.IsRelational())
+        {
+            return true;
+        }
+
+        var connection = db.Database.GetDbConnection();
+        if (connection.State != System.Data.ConnectionState.Open)
+        {
+            await connection.OpenAsync(stoppingToken);
+        }
+
+        await using var command = connection.CreateCommand();
+        command.CommandText = "SELECT EXISTS (SELECT 1 FROM information_schema.tables WHERE table_name = @tableName)";
+        var parameter = command.CreateParameter();
+        parameter.ParameterName = "tableName";
+        parameter.Value = tableName;
+        command.Parameters.Add(parameter);
+
+        var result = await command.ExecuteScalarAsync(stoppingToken);
+        return result is bool exists && exists;
+    }
+
     private static Notification BuildNotification(
         string tipo,
         string titulo,