feat: 未授权时在卡密输入框下方显示本机机器码（带一键复制）v1.8.2

解决用户找不到机器码的问题：去商城购买/手动激活/联系客服都需要提供机器码，现在未授权（试用/体验/异常）状态直接显示并可一键复制；已授权用户不显示，避免界面杂乱。

sidepanel.css

@@ -894,6 +894,46 @@ body {
     background: linear-gradient(135deg, #f57c00, #ff9800);
 }
 
+.machine-code-row {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 8px;
+    margin-top: 6px;
+    font-size: 11px;
+    color: #999;
+}
+
+.machine-code-label {
+    min-width: 0;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+}
+
+.machine-code-label code {
+    font-family: "SF Mono", Consolas, "Courier New", monospace;
+    color: #666;
+    user-select: all;
+}
+
+.machine-code-copy {
+    flex: none;
+    padding: 2px 8px;
+    border: 1px solid #ddd;
+    border-radius: 4px;
+    background: #fff;
+    color: #888;
+    font-size: 11px;
+    cursor: pointer;
+    transition: all 0.2s ease;
+}
+
+.machine-code-copy:hover {
+    border-color: #bbb;
+    color: #444;
+}
+
 .buy-hint {
     margin-top: 8px;
     font-size: 12px;