feat(game): 添加成都麻将游戏页面和大厅功能

- 实现 ChengduGamePage.vue 组件，包含完整的麻将游戏界面
- 实现 HallPage.vue 组件，支持房间列表展示、创建和加入功能
- 添加 mahjong API 接口用于房间管理操作
- 集成 store 状态管理和本地存储功能
- 实现 ChengduBottomActions 等游戏控制组件
- 添加 websocket 连接和游戏会话管理逻辑
- 实现游戏倒计时、结算等功能模块

src/components/chengdu/ChengduSettlementOverlay.vue

@@ -0,0 +1,73 @@
+<script setup lang="ts">
+defineProps<{
+  show: boolean
+  isLastRound: boolean
+  currentRound: number
+  totalRounds: number
+  settlementPlayers: Array<{
+    playerId: string
+    displayName: string
+    score: number
+    isWinner: boolean
+    seatIndex: number
+  }>
+  loggedInUserId: string
+  nextRoundPending: boolean
+  settlementCountdown: number | null
+}>()
+
+const emit = defineEmits<{
+  nextRound: []
+  backHall: []
+}>()
+</script>
+
+<template>
+  <div v-if="show" class="settlement-overlay">
+    <div class="settlement-panel">
+      <h2 class="settlement-title">
+        {{ isLastRound ? '最终结算' : `第 ${currentRound} 局结算` }}
+      </h2>
+      <p v-if="totalRounds > 0" class="settlement-round-info">{{ currentRound }} / {{ totalRounds }} 局</p>
+      <div class="settlement-list">
+        <div
+          v-for="(item, index) in settlementPlayers"
+          :key="item.playerId"
+          class="settlement-row"
+          :class="{ 'is-winner': item.isWinner, 'is-self': item.playerId === loggedInUserId }"
+        >
+          <span class="settlement-rank">{{ index + 1 }}</span>
+          <span class="settlement-name">
+            {{ item.displayName }}
+            <span v-if="item.isWinner" class="settlement-winner-badge">胡</span>
+          </span>
+          <span class="settlement-score" :class="{ 'is-positive': item.score > 0, 'is-negative': item.score < 0 }">
+            {{ item.score > 0 ? '+' : '' }}{{ item.score }}
+          </span>
+        </div>
+      </div>
+      <div class="settlement-actions">
+        <button
+          v-if="!isLastRound"
+          class="ready-toggle ready-toggle-inline settlement-btn"
+          type="button"
+          :disabled="nextRoundPending"
+          @click="emit('nextRound')"
+        >
+          <span class="ready-toggle-label">
+            {{
+              nextRoundPending
+                ? '准备中...'
+                : settlementCountdown != null && settlementCountdown > 0
+                  ? `下一局 (${settlementCountdown}s)`
+                  : '下一局'
+            }}
+          </span>
+        </button>
+        <button v-else class="ready-toggle ready-toggle-inline settlement-btn" type="button" @click="emit('backHall')">
+          <span class="ready-toggle-label">返回大厅</span>
+        </button>
+      </div>
+    </div>
+  </div>
+</template>