Move engineStreamMachine as a global actor; tons of more work

src/lang/std/engineConnection.ts

@@ -841,7 +841,9 @@ class EngineConnection extends EventTarget {
 
             // Bust the cache before anything
             ;(async () => {
-              await clearSceneAndBustCache(kclManager.engineCommandManager)
+              await rustContext.clearSceneAndBustCache(
+                kclManager.engineCommandManager.settings
+              )
             })().catch(reportRejection)
 
             this.dispatchEvent(
@@ -1395,8 +1397,6 @@ export class EngineCommandManager extends EventTarget {
     height: 1337,
   }
 
-  elVideo: HTMLVideoElement | null = null
-
   _commandLogCallBack: (command: CommandLog[]) => void = () => {}
 
   subscriptions: {