fix(inbounds): reject incompatible VLESS fallbacks and prevent Xray crashes (#7003)

Xray refuses a VLESS inbound with server decryption whenever fallbacks is non-nil, even an empty list, so an API or imported inbound with decryption and fallbacks: [] took every inbound down. Empty fallback arrays are now normalized away on add, update, config build and node push; non-empty ones are refused with decryption, enabling decryption over stored fallback rules is refused, and a legacy conflicting row holds back the running core instead of stopping it. The form, API docs and locales follow. Closes #7001.

internal/web/service/xray.go

@@ -214,6 +214,12 @@ func (s *XrayService) GetXrayConfig() (*xray.Config, error) {
 		if inbound.Protocol == model.MTProto || inbound.Protocol == model.AmneziaWG || inbound.Protocol == model.TUIC {
 			continue
 		}
+		if err := normalizeVlessFallbacks(inbound); err != nil {
+			return nil, err
+		}
+		if err := validateVlessManagedFallbacks(nil, inbound); err != nil {
+			return nil, err
+		}
 		settings := map[string]any{}
 		_ = json.Unmarshal([]byte(inbound.Settings), &settings)
 		flowAllowed := !inbound.DisableFlow &&
@@ -1503,6 +1509,9 @@ func (s *XrayService) RestartXray(isForce bool) error {
 
 	xrayConfig, err := s.GetXrayConfig()
 	if err != nil {
+		if process := currentXrayProcess(); process != nil && process.IsRunning() {
+			xrayState.holdBack(fmt.Sprintf("config refused: %v", err))
+		}
 		return err
 	}