Wire view-mode toggles (alt-view + coordinate grid) via new ViewModeController

Moves the AlternateViewEvent / ToggleCoordinateGridEvent subscriptions out of
ClientGameRunner into a dedicated controller in src/client/controllers/. Also
wires ToggleCoordinateGridEvent (M keybind) — previously emitted with no
listener — so the persistent coordinate-grid toggle works. Grid + alt-view
hide names only under alt-view; M keeps names visible.

src/client/hud/GameRenderer.ts

@@ -8,6 +8,7 @@ import { UIState } from "../UIState";
 import { BuildPreviewController } from "../controllers/BuildPreviewController";
 import { HoverHighlightController } from "../controllers/HoverHighlightController";
 import { StructureHighlightController } from "../controllers/StructureHighlightController";
+import { ViewModeController } from "../controllers/ViewModeController";
 import { WarshipSelectionController } from "../controllers/WarshipSelectionController";
 import { GameView as WebGLGameView } from "../render/gl";
 import { FrameProfiler } from "./FrameProfiler";
@@ -281,6 +282,7 @@ export function createRenderer(
     ),
     new HoverHighlightController(game, eventBus, transformHandler, view),
     new StructureHighlightController(eventBus, view),
+    new ViewModeController(eventBus, view),
     new AttackingTroopsOverlay(game, transformHandler, eventBus, userSettings),
     eventsDisplay,
     actionableEvents,