feat(simnet): add SimNet protocol end-to-end support

- model: SimNet protocol fields + NormalizeSimnet; type+port protocol uniqueness
- server config: OmnXT runtime config delivery via compatible() simnet case
- credentials: derive per-user psk/key_id from subscription (pkg/simnet), no new table
- subscription: adapter buildOmnxtSimnetConfigs + base64 buildOmnxtProtocolLinks + OmnXT SimNet application (migration 02161)
- UA gating: hide experimental protocols from non first-party clients (download + JSON node-list)
- admin: normalize simnet on create/update and on GET responses
- tests: 21 simnet unit tests; full suite green

internal/logic/public/subscribe/queryUserSubscribeNodeListLogic.go

@@ -13,6 +13,7 @@ import (
 	"github.com/perfect-panel/server/internal/types"
 	"github.com/perfect-panel/server/pkg/constant"
 	"github.com/perfect-panel/server/pkg/logger"
+	"github.com/perfect-panel/server/pkg/simnet"
 	"github.com/perfect-panel/server/pkg/tool"
 	"github.com/perfect-panel/server/pkg/xerr"
 	"github.com/pkg/errors"
@@ -20,16 +21,18 @@ import (
 
 type QueryUserSubscribeNodeListLogic struct {
 	logger.Logger
-	ctx    context.Context
-	svcCtx *svc.ServiceContext
+	ctx       context.Context
+	svcCtx    *svc.ServiceContext
+	userAgent string
 }
 
 // Get user subscribe node info
-func NewQueryUserSubscribeNodeListLogic(ctx context.Context, svcCtx *svc.ServiceContext) *QueryUserSubscribeNodeListLogic {
+func NewQueryUserSubscribeNodeListLogic(ctx context.Context, svcCtx *svc.ServiceContext, userAgent string) *QueryUserSubscribeNodeListLogic {
 	return &QueryUserSubscribeNodeListLogic{
-		Logger: logger.WithContext(ctx),
-		ctx:    ctx,
-		svcCtx: svcCtx,
+		Logger:    logger.WithContext(ctx),
+		ctx:       ctx,
+		svcCtx:    svcCtx,
+		userAgent: userAgent,
 	}
 }
 
@@ -163,6 +166,12 @@ func (l *QueryUserSubscribeNodeListLogic) getServers(userSub *user.Subscribe) (u
 			if server == nil {
 				continue
 			}
+			// Hide experimental protocols (simnet) — and their server material in
+			// the raw protocols JSON — from non first-party clients. Mirrors the
+			// Pro reference FilterExperimentalNodesForClient.
+			if simnet.IsExperimentalProtocol(n.Protocol) && !simnet.ClientSupportsExperimental(l.userAgent) {
+				continue
+			}
 			userSubscribeNode := &types.UserSubscribeNodeInfo{
 				Id:              n.Id,
 				Name:            n.Name,