feat: v1.2.0 房间详情/聊天/踢人 + 速率限制 + WebSocket增强

Server:
- API速率限制中间件 (120 req/min per IP, X-RateLimit headers)
- 房间聊天API: POST /rooms/:id/chat
- 认证中间件放行公开GET路由和房间join
- WebSocket: 房间订阅/取消订阅 (subscribe/unsubscribe)
- WebSocket: 房间聊天广播 (chat -> broadcastToRoom)
- WebSocket: 房间事件通知 (roomCreated/Deleted/playerJoined/Left)

Client:
- 房间详情弹窗: 点击房间卡片打开
  - 房间信息网格 (房间号/房主/版本/人数)
  - 在线玩家列表 (5秒自动刷新)
  - 踢出玩家 (确认对话框)
  - 房间聊天 (实时发送/显示)
  - 加入房间 / 删除房间按钮
- 连接状态指示器动画 (online/offline/connecting)
- 房间卡片hover效果
- 版本更新到 v1.2.0
- ApiClient: 新增 getRoomDetail/kickPlayer/sendChat
- Preload: 新增对应IPC方法
- Main: 新增 rooms:detail/kick/chat handlers

client/renderer/index.html

@@ -57,7 +57,7 @@
           <span class="nav-icon">ℹ️</span> 关于
         </li>
       </ul>
-      <div class="sidebar-footer">v1.0.0</div>
+      <div class="sidebar-footer">v1.2.0</div>
     </nav>
 
     <!-- Content -->
@@ -233,7 +233,7 @@
           <div class="about-header">
             <div class="about-logo">F</div>
             <div>
-              <h3>FunConnect v1.0.0</h3>
+              <h3>FunConnect v1.2.0</h3>
               <p>Minecraft 联机客户端</p>
             </div>
           </div>
@@ -273,6 +273,35 @@
     </main>
   </div>
 
+  <!-- Room Detail Modal -->
+  <div class="modal-overlay hidden" id="modal-overlay">
+    <div class="modal" id="room-detail-modal">
+      <div class="modal-header">
+        <h3 id="modal-room-name">房间详情</h3>
+        <button class="modal-close" id="modal-close">&times;</button>
+      </div>
+      <div class="modal-body">
+        <div class="modal-info" id="modal-room-info"></div>
+        <div class="modal-section">
+          <h4>在线玩家 <span id="modal-player-count"></span></h4>
+          <div id="modal-player-list" class="player-list"></div>
+        </div>
+        <div class="modal-section">
+          <h4>房间聊天</h4>
+          <div id="modal-chat-messages" class="chat-messages"></div>
+          <div class="chat-input-row">
+            <input type="text" id="modal-chat-input" class="input" placeholder="输入消息...">
+            <button class="btn btn-primary btn-sm" id="modal-chat-send">发送</button>
+          </div>
+        </div>
+      </div>
+      <div class="modal-footer">
+        <button class="btn btn-secondary" id="modal-join-btn">加入此房间</button>
+        <button class="btn btn-danger" id="modal-delete-btn">删除房间</button>
+      </div>
+    </div>
+  </div>
+
   <script src="app.js"></script>
 </body>
 </html>