feat(frontend): 菜单组件 — 主菜单/本地双人/AI设置/网络/加载棋谱

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/components/menu/OnlineSetup.tsx

@@ -0,0 +1,39 @@
+import { useTranslation } from 'react-i18next';
+import { useGameStore } from '../../store/gameStore';
+import { useState } from 'react';
+import type { GameConfig } from '../../core/types';
+
+interface Props { onBack: () => void; onStart: () => void; }
+
+export default function OnlineSetup({ onBack, onStart }: Props) {
+  const { t } = useTranslation();
+  const startGame = useGameStore((s) => s.startGame);
+  const [ip, setIp] = useState('');
+
+  const baseConfig: GameConfig = {
+    boardSize: 15, useForbiddenRules: true, useTimer: false,
+    timeLimitSecs: 60, aiDifficulty: 3, playerColor: 'Black', isServer: false,
+  };
+
+  const handleHost = async () => {
+    await startGame('Online', { ...baseConfig, isServer: true });
+    onStart();
+  };
+
+  const handleJoin = async () => {
+    await startGame('Online', { ...baseConfig });
+    onStart();
+  };
+
+  return (
+    <div className="setup-panel">
+      <h2>{t('menu.online_game')}</h2>
+      <button onClick={handleHost}>创建房间</button>
+      <div style={{ display: 'flex', gap: 8, marginTop: 12 }}>
+        <input value={ip} onChange={(e) => setIp(e.target.value)} placeholder="IP:端口" />
+        <button onClick={handleJoin} disabled={!ip}>加入房间</button>
+      </div>
+      <button onClick={onBack} style={{ marginTop: 12 }}>返回</button>
+    </div>
+  );
+}