feat(push): smart push queueing with page-visibility fast path and app-ping/pong fallback

src/lib/ws.ts

@@ -41,6 +41,8 @@ export class WsClient {
       if (this.activeSessionId) {
         this.send({ type: WS.RECONNECT, sessionId: this.activeSessionId, adapter: this.activeAdapter });
       }
+      // Tell server our current visibility state immediately on (re)connect
+      this.send({ type: WS.PAGE_VISIBILITY, visible: document.visibilityState === 'visible' });
     };
 
     this.ws.onmessage = (event) => {
@@ -50,6 +52,14 @@ export class WsClient {
           this.activeSessionId = msg.sessionId;
           if (msg.adapter) this.activeAdapter = msg.adapter;
         }
+        // Respond to server app-ping only when page is visible.
+        // If hidden, no pong → server fires push after 2s timeout.
+        if (msg.type === WS.APP_PING) {
+          if (document.visibilityState === 'visible') {
+            this.send({ type: WS.APP_PONG, sessionId: msg.sessionId });
+          }
+          return;
+        }
         this.onMessage(msg);
       } catch (err) {
         console.error('[ws] Failed to parse message:', err);
@@ -109,12 +119,13 @@ export class WsClient {
   private _startVisibilityWatch() {
     if (this.visibilityHandler) return;
     this.visibilityHandler = () => {
-      if (document.visibilityState === 'hidden') {
+      const visible = document.visibilityState === 'visible';
+      this.send({ type: WS.PAGE_VISIBILITY, visible });
+      if (!visible) {
         this.hiddenSince = Date.now();
-      } else if (document.visibilityState === 'visible' && this.shouldReconnect) {
+      } else if (this.shouldReconnect) {
         const elapsed = this.hiddenSince ? Date.now() - this.hiddenSince : 0;
         this.hiddenSince = null;
-        // Only force reconnect if page was hidden long enough for the WS to go stale
         if (elapsed >= VISIBILITY_RECONNECT_THRESHOLD) {
           this.forceReconnect();
         }