feat(wireguard): client config UX, collapsible config card, configurable DNS

Land the WireGuard client-config UX work on main (the upstream PR #5642
branch could not be pushed to).

- Reusable collapsible ConfigBlock (copy/download/QR, actions aligned right)
  for the client .conf, used by client info and the public sub page.
- Correct .conf: canonical PresharedKey casing and DNS sourced from the inbound
  (configurable per-inbound, default 1.1.1.1, 1.0.0.1).
- Configurable per-inbound DNS for WireGuard (schema + form + backend hint via
  InboundOption.WgDns); inert at the Xray layer.
- Public sub page now shows the WireGuard config, rebuilt from the share link;
  the Go wireguard:// link carries dns/presharedkey/keepalive for completeness.
- QR enabled for the wireguard:// link; link rows are compact like other protocols.
- Client information order is subscription, copy URL, WireGuard config; the
  redundant config tab is removed from the add/edit client modal.
- Drop the Inbound Information and QR Code row actions for WireGuard inbounds.

frontend/src/components/clients/ConfigBlock.css

@@ -0,0 +1,40 @@
+.config-block {
+  margin-bottom: 10px;
+}
+
+.config-block .ant-collapse-header {
+  align-items: center !important;
+  padding: 8px 12px !important;
+}
+
+.config-block .ant-collapse-header-text {
+  flex: 1;
+  min-width: 0;
+}
+
+.config-block .ant-collapse-extra {
+  display: flex;
+  align-items: center;
+}
+
+.config-block-actions {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+}
+
+.config-block .ant-collapse-content-box {
+  padding: 8px !important;
+}
+
+.config-block-text {
+  display: block;
+  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
+  font-size: 11px;
+  word-break: break-all;
+  white-space: pre-wrap;
+  padding: 6px 8px;
+  background: var(--ant-color-fill-tertiary);
+  border-radius: 4px;
+  user-select: all;
+}

frontend/src/components/clients/ConfigBlock.tsx

@@ -0,0 +1,79 @@
+import type { MouseEvent } from 'react';
+import { useTranslation } from 'react-i18next';
+import { Button, Collapse, Popover, Tag, Tooltip, message } from 'antd';
+import { CopyOutlined, DownloadOutlined, QrcodeOutlined } from '@ant-design/icons';
+
+import { ClipboardManager, FileManager } from '@/utils';
+import { QrPanel } from '@/pages/inbounds/qr';
+import './ConfigBlock.css';
+
+interface ConfigBlockProps {
+  label: string;
+  text: string;
+  fileName: string;
+  qrRemark?: string;
+  showQr?: boolean;
+  tagColor?: string;
+  defaultOpen?: boolean;
+}
+
+export default function ConfigBlock({
+  label,
+  text,
+  fileName,
+  qrRemark = '',
+  showQr = true,
+  tagColor = 'gold',
+  defaultOpen = false,
+}: ConfigBlockProps) {
+  const { t } = useTranslation();
+  const [messageApi, messageContextHolder] = message.useMessage();
+
+  async function copy() {
+    const ok = await ClipboardManager.copyText(text);
+    if (ok) messageApi.success(t('copied'));
+  }
+
+  const actions = (
+    <div className="config-block-actions" onClick={(e: MouseEvent) => e.stopPropagation()}>
+      <Tooltip title={t('copy')}>
+        <Button size="small" icon={<CopyOutlined />} onClick={copy} />
+      </Tooltip>
+      <Tooltip title={t('download')}>
+        <Button
+          size="small"
+          icon={<DownloadOutlined />}
+          onClick={() => FileManager.downloadTextFile(text, fileName)}
+        />
+      </Tooltip>
+      {showQr && (
+        <Popover
+          trigger="click"
+          placement="left"
+          destroyOnHidden
+          content={<QrPanel value={text} remark={qrRemark || label} size={220} />}
+        >
+          <Tooltip title={t('pages.clients.qrCode')}>
+            <Button size="small" icon={<QrcodeOutlined />} />
+          </Tooltip>
+        </Popover>
+      )}
+    </div>
+  );
+
+  return (
+    <>
+      {messageContextHolder}
+      <Collapse
+        className="config-block"
+        defaultActiveKey={defaultOpen ? ['cfg'] : []}
+        items={[{
+          key: 'cfg',
+          label: <Tag color={tagColor} style={{ margin: 0, fontWeight: 600, letterSpacing: '0.3px' }}>{label}</Tag>,
+          extra: actions,
+          children: <code className="config-block-text">{text}</code>,
+        }]}
+      />
+    </>
+  );
+}