fix: PSK 复制兼容 HTTP 环境（execCommand 降级）

web/src/views/Psks.vue

@@ -166,7 +166,20 @@ const handleToggle = async (row) => {
 
 const copySecret = async (secret) => {
   try {
-    await navigator.clipboard.writeText(secret)
+    // 优先 clipboard API（需要 HTTPS）
+    if (navigator.clipboard && window.isSecureContext) {
+      await navigator.clipboard.writeText(secret)
+    } else {
+      // HTTP 降级：execCommand
+      const textarea = document.createElement('textarea')
+      textarea.value = secret
+      textarea.style.position = 'fixed'
+      textarea.style.opacity = '0'
+      document.body.appendChild(textarea)
+      textarea.select()
+      document.execCommand('copy')
+      document.body.removeChild(textarea)
+    }
     ElMessage.success('已复制到剪贴板')
   } catch {
     ElMessage.error('复制失败，请手动复制')