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.

internal/sub/service.go

@@ -545,6 +545,15 @@ func (s *SubService) genWireguardLink(inbound *model.Inbound, email string) stri
 	if mtu, ok := settings["mtu"].(float64); ok && mtu > 0 {
 		params["mtu"] = strconv.Itoa(int(mtu))
 	}
+	if dns, ok := settings["dns"].(string); ok && dns != "" {
+		params["dns"] = dns
+	}
+	if client.PreSharedKey != "" {
+		params["presharedkey"] = client.PreSharedKey
+	}
+	if client.KeepAlive > 0 {
+		params["keepalive"] = strconv.Itoa(client.KeepAlive)
+	}
 	return buildLinkWithParams(link, params, s.genRemark(inbound, email, "", ""))
 }