move TransformHandler/UIState/Controller out of graphics/, drop dead GhostStructureChangedEvent

graphics/ was a canvas2D-era directory name — TransformHandler, UIState,
and the Controller interface aren't graphics, they're cross-cutting
client state. Hoist them to src/client/ so the path matches what they
are. GhostStructureChangedEvent had three emitters and zero listeners;
removed.

src/client/InputHandler.ts

@@ -2,8 +2,8 @@ import { EventBus, GameEvent } from "../core/EventBus";
 import { PlayerBuildableUnitType, UnitType } from "../core/game/Game";
 import { GameView, UnitView } from "../core/game/GameView";
 import { UserSettings } from "../core/game/UserSettings";
-import { UIState } from "./graphics/UIState";
 import { Platform } from "./Platform";
+import { UIState } from "./UIState";
 import { ReplaySpeedMultiplier } from "./utilities/ReplaySpeedMultiplier";
 
 export class MouseUpEvent implements GameEvent {
@@ -92,10 +92,6 @@ export class ToggleStructureEvent implements GameEvent {
   ) {}
 }
 
-export class GhostStructureChangedEvent implements GameEvent {
-  constructor(public readonly ghostStructure: PlayerBuildableUnitType | null) {}
-}
-
 export class ConfirmGhostStructureEvent implements GameEvent {}
 
 export class SwapRocketDirectionEvent implements GameEvent {
@@ -850,7 +846,6 @@ export class InputHandler {
 
   private setGhostStructure(ghostStructure: PlayerBuildableUnitType | null) {
     this.uiState.ghostStructure = ghostStructure;
-    this.eventBus.emit(new GhostStructureChangedEvent(ghostStructure));
   }
 
   /**