feat(GatewayAutocomplete): simplify country flag rendering and display provider information for selected gateways

frontend/src/FilterManager.jsx

@@ -433,7 +433,7 @@ function GatewayAutocomplete({ label, value, onChange, gateways = [], required =
       <div className="mt-2">
         <div className="d-flex align-items-center gap-2 p-2 bg-light rounded">
           <span className="avatar avatar-xs bg-primary-lt">
-            {selectedGateway.country ? countryToFlag(selectedGateway.country) : <IconServer size={14} />}
+            {countryToFlag(selectedGateway.country || '')}
           </span>
           <div className="flex-grow-1">
             <div className="fw-bold">
@@ -443,6 +443,12 @@ function GatewayAutocomplete({ label, value, onChange, gateways = [], required =
             <div className="text-muted small">
               {[selectedGateway.serverDns].filter(Boolean).join(' · ')}
             </div>
+            {(selectedGateway.country || selectedGateway.provider) && (
+              <div className="text-muted small mt-1">
+                {selectedGateway.country && <span className="me-1">{countryToFlag(selectedGateway.country)}</span>}
+                {selectedGateway.provider}
+              </div>
+            )}
           </div>
           {selectedGateway.primary && <span className="badge bg-green-lt text-green">Основной</span>}
         </div>
@@ -518,7 +524,7 @@ function GatewayAutocomplete({ label, value, onChange, gateways = [], required =
                       <div className="card-body py-2 px-3">
                         <div className="d-flex align-items-start gap-2 mb-1">
                           <span className={`avatar avatar-sm ${isSelected ? 'bg-white text-primary' : 'bg-primary-lt'}`}>
-                            {gw.country ? countryToFlag(gw.country) : <IconServer size={16} />}
+                            {countryToFlag(gw.country || '')}
                           </span>
                           <div className="flex-grow-1 min-w-0">
                             <div className="fw-bold text-truncate">