Release 3.8.2.5: cheaper idle UI poll and tighter hot paths.

Delta getState by rev, pause when hidden, cancellable background loops,
hostCache bounds, unlock PollUI around engine status, corebin singleflight,
PingAll worker pool.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/netcheck/ping.go

@@ -57,20 +57,26 @@ func PingAll(ctx context.Context, targets []Target) []Result {
 	if len(targets) < workers {
 		workers = len(targets)
 	}
-	sem := make(chan struct{}, workers)
+	jobs := make(chan int, len(targets))
+	for i := range targets {
+		jobs <- i
+	}
+	close(jobs)
+
 	var wg sync.WaitGroup
-	for i, t := range targets {
+	for w := 0; w < workers; w++ {
 		wg.Add(1)
-		go func(i int, t Target) {
+		go func() {
 			defer wg.Done()
-			sem <- struct{}{}
-			defer func() { <-sem }()
-			if strings.TrimSpace(t.Proxy) == "" {
-				out[i] = Result{Name: t.Name, Error: "нет ссылки сервера"}
-				return
+			for i := range jobs {
+				t := targets[i]
+				if strings.TrimSpace(t.Proxy) == "" {
+					out[i] = Result{Name: t.Name, Error: "нет ссылки сервера"}
+					continue
+				}
+				out[i] = PingProfile(ctx, t.Name, t.Protocol, t.Proxy)
 			}
-			out[i] = PingProfile(ctx, t.Name, t.Protocol, t.Proxy)
-		}(i, t)
+		}()
 	}
 	wg.Wait()