Preserve outbound backlog across outages, fix backoff quiet period

test/RuntimeSpec.hs

@@ -3,7 +3,7 @@ module RuntimeSpec (spec) where
 
 import Control.Concurrent (threadDelay)
 import Control.Concurrent.Async (async)
-import Control.Concurrent.STM (atomically, readTChan, writeTChan)
+import Control.Concurrent.STM (atomically, isEmptyTChan, readTChan, writeTChan)
 import Data.Aeson (Value, object, (.=))
 import Data.Text (Text)
 import HomeAssistant.Controller (light, lightController)
@@ -24,6 +24,7 @@ spec = describe "runController" $ do
     svc2 <- atomically (readTChan (busOutbound bus))
     svc1 `shouldBe` light True
     svc2 `shouldBe` light False
+    atomically (isEmptyTChan (busOutbound bus)) `shouldReturn` True
 
 doorEvent :: Text -> Value
 doorEvent state = object