feat(inbounds): add sub/client link endpoints; hide panel version on login

- New GET /panel/api/inbounds/getSubLinks/:subId and /getClientLinks/:id/:email
  return the same protocol URLs the panel UI's Copy button emits, honouring
  X-Forwarded-Host / X-Forwarded-Proto. Documented in the API docs page.
- Refactor: sub package no longer imports web. The embedded dist FS is
  injected via sub.SetDistFS, and the link generator is registered with the
  service layer via service.RegisterSubLinkProvider, avoiding the circular
  import the new endpoints would otherwise introduce.
- Security: stop emitting window.X_UI_CUR_VER on login.html and drop the
  visible version chip from the login page, so the panel version is no
  longer pre-auth info disclosure. Authenticated pages still receive it.
- Bump config/version.

web/service/inbound.go

@@ -3866,3 +3866,31 @@ func (s *InboundService) DelInboundClientByEmail(inboundId int, email string) (b
 
 	return needRestart, db.Save(oldInbound).Error
 }
+
+type SubLinkProvider interface {
+	SubLinksForSubId(host, subId string) ([]string, error)
+	LinksForClient(host string, inbound *model.Inbound, email string) []string
+}
+
+var registeredSubLinkProvider SubLinkProvider
+
+func RegisterSubLinkProvider(p SubLinkProvider) {
+	registeredSubLinkProvider = p
+}
+
+func (s *InboundService) GetSubLinks(host, subId string) ([]string, error) {
+	if registeredSubLinkProvider == nil {
+		return nil, common.NewError("sub link provider not registered")
+	}
+	return registeredSubLinkProvider.SubLinksForSubId(host, subId)
+}
+func (s *InboundService) GetClientLinks(host string, id int, email string) ([]string, error) {
+	inbound, err := s.GetInbound(id)
+	if err != nil {
+		return nil, err
+	}
+	if registeredSubLinkProvider == nil {
+		return nil, common.NewError("sub link provider not registered")
+	}
+	return registeredSubLinkProvider.LinksForClient(host, inbound, email), nil
+}