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;
+}