perf(core): speed up packedTileUpdates (Uint32 pairs, no tile wrappers) (#3255)

## Description
Reduces CPU + GC pressure from tile update serialization.

**What changed**
- Switched `packedTileUpdates` from `BigUint64Array` (BigInt packing) to
`Uint32Array` `[tileRef, state]` pairs, updating `GameView` ingestion.
- Updated tile state to use `GameMap.tileState(tile)` and
`GameMap.updateTile(tile, state)`.
- Removed per-tile `GameUpdateType.Tile` wrapper allocations by
recording raw `(tile, state)` pairs in `GameImpl` and draining them via
`drainPackedTileUpdates()` in `GameRunner`.

**Why it’s faster**
- Avoids BigInt and pack/unpack.
- Avoids per-tile object allocations.

**Compatibility**
- Wire format change: `packedTileUpdates` is now `Uint32Array` pairs
instead of `BigUint64Array`.

## Please complete the following:

- [ ] I have added screenshots for all UI updates
- [ ] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [ ] I have added relevant tests to the test directory
- [ ] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

DISCORD_USERNAME

src/core/game/GameUpdates.ts

@@ -12,12 +12,18 @@ import {
   TrainType,
   UnitType,
 } from "./Game";
-import { TileRef, TileUpdate } from "./GameMap";
+import { TileRef } from "./GameMap";
 
 export interface GameUpdateViewData {
   tick: number;
   updates: GameUpdates;
-  packedTileUpdates: BigUint64Array;
+  /**
+   * Packed tile updates as `[tileRef, state]` uint32 pairs.
+   *
+   * `tileRef` is a `TileRef` (fits in uint32), and `state` is the packed per-tile
+   * state (`uint16`) stored in a `uint32` lane.
+   */
+  packedTileUpdates: Uint32Array;
   playerNameViewData: Record<string, NameViewData>;
   tickExecutionDuration?: number;
   pendingTurns?: number;
@@ -29,6 +35,7 @@ export interface ErrorUpdate {
 }
 
 export enum GameUpdateType {
+  // Tile updates are delivered via `packedTileUpdates` on the outer GameUpdateViewData.
   Tile,
   Unit,
   Player,
@@ -54,7 +61,6 @@ export enum GameUpdateType {
 }
 
 export type GameUpdate =
-  | TileUpdateWrapper
   | UnitUpdate
   | PlayerUpdate
   | AllianceRequestUpdate
@@ -112,11 +118,6 @@ export interface ConquestUpdate {
   gold: Gold;
 }
 
-export interface TileUpdateWrapper {
-  type: GameUpdateType.Tile;
-  update: TileUpdate;
-}
-
 export interface UnitUpdate {
   type: GameUpdateType.Unit;
   unitType: UnitType;