feat: 新增 /拍一拍 功能 + 斜杠命令菜单

- 输入框输入 / 弹出命令菜单，当前支持 /拍一拍
- 选择对象后输入 /拍一拍 发送拍一拍通知
- 所有在线用户屏幕抖动 + 正常聊天样式显示消息
- 命令注册表可扩展，后续新增命令只需 push 到数组

resources/js/chat-room/composer.js

@@ -177,6 +177,18 @@ async function sendMessage(e) {
     const composerState = collectChatComposerState();
     const { contentInput, submitBtn, content, contentRaw, selectedImage, toUser } = composerState;
 
+    // 拦截 /拍一拍 命令：使用当前选中的聊天对象
+    if (content && typeof window.isPatCommand === "function" && window.isPatCommand(content)) {
+        if (state) {
+            state.isSending = false;
+            state.sendStartedAt = 0;
+        }
+        if (typeof window.executePat === "function") {
+            await window.executePat();
+        }
+        return;
+    }
+
     if (!content && !selectedImage) {
         contentInput?.focus();
         if (state) {