Document and harden curated critical imports

src/RolemasterDb.App/Data/RolemasterDbSchemaUpgrader.cs

@@ -94,6 +94,11 @@ public static class RolemasterDbSchemaUpgrader
 
     private static async Task EnsureCriticalResultCurationColumnsAsync(RolemasterDbContext dbContext, CancellationToken cancellationToken)
     {
+        if (!await TableExistsAsync(dbContext, "CriticalResults", cancellationToken))
+        {
+            return;
+        }
+
         if (!await ColumnExistsAsync(dbContext, "CriticalResults", "IsCurated", cancellationToken))
         {
             await dbContext.Database.ExecuteSqlRawAsync(
@@ -195,4 +200,38 @@ public static class RolemasterDbSchemaUpgrader
             }
         }
     }
+
+    private static async Task<bool> TableExistsAsync(
+        RolemasterDbContext dbContext,
+        string tableName,
+        CancellationToken cancellationToken)
+    {
+        var connection = dbContext.Database.GetDbConnection();
+        var shouldClose = connection.State != System.Data.ConnectionState.Open;
+        if (shouldClose)
+        {
+            await connection.OpenAsync(cancellationToken);
+        }
+
+        try
+        {
+            await using var command = connection.CreateCommand();
+            command.CommandText = "SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = $tableName;";
+
+            var parameter = command.CreateParameter();
+            parameter.ParameterName = "$tableName";
+            parameter.Value = tableName;
+            command.Parameters.Add(parameter);
+
+            var result = await command.ExecuteScalarAsync(cancellationToken);
+            return Convert.ToInt32(result) > 0;
+        }
+        finally
+        {
+            if (shouldClose)
+            {
+                await connection.CloseAsync();
+            }
+        }
+    }
 }