feat(gs/xanthous): Allow disabling saving

Add a command-line parameter to disable the Save command, so people
don't save and fill up my disk when I'm running this on the internet.

Change-Id: I2408e60de2d99764ac53c21c3ea784282576d400
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3808
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

users/grfn/xanthous/src/Xanthous/Game/Env.hs

@@ -1,8 +1,12 @@
 {-# LANGUAGE TemplateHaskell #-}
 --------------------------------------------------------------------------------
 module Xanthous.Game.Env
-  ( GameEnv(..)
+  ( Config(..)
+  , defaultConfig
+  , disableSaving
+  , GameEnv(..)
   , eventChan
+  , config
   ) where
 --------------------------------------------------------------------------------
 import Xanthous.Prelude
@@ -11,9 +15,23 @@ import Brick.BChan (BChan)
 import Xanthous.Data.App (AppEvent)
 --------------------------------------------------------------------------------
 
+data Config = Config
+  { _disableSaving :: Bool
+  }
+  deriving stock (Generic, Show, Eq)
+makeLenses ''Config
+{-# ANN Config ("HLint: ignore Use newtype instead of data" :: String) #-}
+
+defaultConfig :: Config
+defaultConfig = Config
+  { _disableSaving = False
+  }
+
+--------------------------------------------------------------------------------
+
 data GameEnv = GameEnv
   { _eventChan :: BChan AppEvent
+  , _config :: Config
   }
   deriving stock (Generic)
 makeLenses ''GameEnv
-{-# ANN GameEnv ("HLint: ignore Use newtype instead of data" :: String) #-}