feat: 전투 시뮬레이터를 브라우저 Worker로 이관

서버가 권위 환경과 반복 seed를 준비하고 공용 logic 프로세서를 브라우저와 기존 서버 fallback이 함께 사용하도록 변경한다. production Chromium에서 고정 seed와 1000회 Node 결과 동등성을 검증한다.

app/game-frontend/src/utils/battleSimulatorWorkerClient.ts

@@ -0,0 +1,81 @@
+import type { BattleSimJobPayload, BattleSimResultPayload } from '@sammo-ts/logic';
+
+import type { BattleSimulatorWorkerRequest, BattleSimulatorWorkerResponse } from './battleSimulatorWorkerProtocol';
+
+type PendingRequest = {
+    resolve: (result: BattleSimResultPayload) => void;
+    reject: (error: Error) => void;
+};
+
+export class BattleSimulatorWorkerClient {
+    private worker: Worker | null = null;
+    private nextRequestId = 1;
+    private readonly pending = new Map<number, PendingRequest>();
+
+    private ensureWorker(): Worker {
+        if (this.worker) {
+            return this.worker;
+        }
+
+        const worker = new Worker(new URL('../workers/battleSimulator.worker.ts', import.meta.url), {
+            type: 'module',
+            name: 'sammo-battle-simulator',
+        });
+        worker.addEventListener('message', this.handleMessage);
+        worker.addEventListener('error', this.handleWorkerError);
+        this.worker = worker;
+        return worker;
+    }
+
+    private readonly handleMessage = (event: MessageEvent<BattleSimulatorWorkerResponse>): void => {
+        const pending = this.pending.get(event.data.requestId);
+        if (!pending) {
+            return;
+        }
+        this.pending.delete(event.data.requestId);
+        if (event.data.ok) {
+            pending.resolve(event.data.result);
+            return;
+        }
+        pending.reject(new Error(event.data.error));
+    };
+
+    private readonly handleWorkerError = (event: ErrorEvent): void => {
+        const error = new Error(event.message || '전투 시뮬레이션 worker 오류');
+        for (const pending of this.pending.values()) {
+            pending.reject(error);
+        }
+        this.pending.clear();
+        this.disposeWorker();
+    };
+
+    public run(payload: BattleSimJobPayload): Promise<BattleSimResultPayload> {
+        const requestId = this.nextRequestId;
+        this.nextRequestId += 1;
+        const request: BattleSimulatorWorkerRequest = { requestId, payload };
+        const promise = new Promise<BattleSimResultPayload>((resolve, reject) => {
+            this.pending.set(requestId, { resolve, reject });
+        });
+        this.ensureWorker().postMessage(request);
+        return promise;
+    }
+
+    private disposeWorker(): void {
+        if (!this.worker) {
+            return;
+        }
+        this.worker.removeEventListener('message', this.handleMessage);
+        this.worker.removeEventListener('error', this.handleWorkerError);
+        this.worker.terminate();
+        this.worker = null;
+    }
+
+    public dispose(): void {
+        const error = new Error('전투 시뮬레이션이 취소되었습니다.');
+        for (const pending of this.pending.values()) {
+            pending.reject(error);
+        }
+        this.pending.clear();
+        this.disposeWorker();
+    }
+}

app/game-frontend/src/utils/battleSimulatorWorkerProtocol.ts

@@ -0,0 +1,18 @@
+import type { BattleSimJobPayload, BattleSimResultPayload } from '@sammo-ts/logic';
+
+export interface BattleSimulatorWorkerRequest {
+    requestId: number;
+    payload: BattleSimJobPayload;
+}
+
+export type BattleSimulatorWorkerResponse =
+    | {
+          requestId: number;
+          ok: true;
+          result: BattleSimResultPayload;
+      }
+    | {
+          requestId: number;
+          ok: false;
+          error: string;
+      };