feat: track WebSocket subscriptions in metrics

Add metrics tracking for WebSocket (NIP-01) subscriptions in addition
to existing gRPC subscription tracking.

Changes:
- Add Count() method to subscription.Manager
- Add MetricsRecorder interface to WebSocket handler
- Update subscription metrics when REQ/CLOSE messages processed
- Wire up metrics to WebSocket handler in main.go

Before: Only gRPC stream subscriptions were counted
After: Both gRPC and WebSocket subscriptions tracked accurately

This fixes the dashboard showing 0 subscriptions when clients connect
via WebSocket (e.g., nak req --stream).

1 files changed, 27 insertions, 0 deletions

diff --git a/internal/handler/websocket/handler.go b/internal/handler/websocket/handler.go
index 5d40abb..b7ea71d 100644
--- a/internal/handler/websocket/handler.go
+++ b/internal/handler/websocket/handler.go
@@ -20,9 +20,16 @@ type EventStore interface {
         ProcessDeletion(context.Context, *pb.Event) error
 }
 
+type MetricsRecorder interface {
+        IncrementSubscriptions()
+        DecrementSubscriptions()
+        SetActiveSubscriptions(count int)
+}
+
 type Handler struct {
         store     EventStore
         subs      *subscription.Manager
+        metrics   MetricsRecorder
         indexData IndexData
 }
 
@@ -33,6 +40,10 @@ func NewHandler(store EventStore, subs *subscription.Manager) *Handler {
         }
 }
 
+func (h *Handler) SetMetrics(m MetricsRecorder) {
+        h.metrics = m
+}
+
 // SetIndexData sets the addresses for the index page
 func (h *Handler) SetIndexData(grpcAddr, httpAddr, wsAddr string) {
         h.indexData = IndexData{
@@ -69,9 +80,15 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
         ctx := r.Context()
         clientSubs := make(map[string]*subscription.Subscription)
         defer func() {
+                count := len(clientSubs)
                 for subID := range clientSubs {
                         h.subs.Remove(subID)
                 }
+                if h.metrics != nil && count > 0 {
+                        for i := 0; i < count; i++ {
+                                h.metrics.DecrementSubscriptions()
+                        }
+                }
         }()
 
         for {
@@ -192,6 +209,9 @@ func (h *Handler) handleReq(ctx context.Context, conn *websocket.Conn, raw []jso
         if existing, ok := clientSubs[subID]; ok {
                 h.subs.Remove(existing.ID)
                 delete(clientSubs, subID)
+                if h.metrics != nil {
+                        h.metrics.DecrementSubscriptions()
+                }
         }
 
         storedEvents, err := h.store.QueryEvents(ctx, filters, &storage.QueryOptions{Limit: 0})
@@ -216,6 +236,10 @@ func (h *Handler) handleReq(ctx context.Context, conn *websocket.Conn, raw []jso
         h.subs.Add(sub)
         clientSubs[subID] = sub
 
+        if h.metrics != nil {
+                h.metrics.IncrementSubscriptions()
+        }
+
         go h.streamEvents(ctx, conn, sub)
 
         return nil
@@ -234,6 +258,9 @@ func (h *Handler) handleClose(raw []json.RawMessage, clientSubs map[string]*subs
         if sub, ok := clientSubs[subID]; ok {
                 h.subs.Remove(sub.ID)
                 delete(clientSubs, subID)
+                if h.metrics != nil {
+                        h.metrics.DecrementSubscriptions()
+                }
         }
 
         return nil