chore: build with Go 1.26; use Go 1.25 features (#10570)

WaitGroup.Go and built-in gomaxprocs handling.

Signed-off-by: Jakob Borg <jakob@kastelo.net>

cmd/infra/strelaypoolsrv/stats.go

@@ -108,8 +108,7 @@ func refreshStats() {
 
 	results := make(chan statsFetchResult, len(relays))
 	for _, rel := range relays {
-		wg.Add(1)
-		go func(rel *relay) {
+		wg.Go(func() {
 			t0 := time.Now()
 			stats := fetchStats(rel)
 			duration := time.Since(t0).Seconds()
@@ -123,8 +122,7 @@ func refreshStats() {
 				relay: rel,
 				stats: fetchStats(rel),
 			}
-			wg.Done()
-		}(rel)
+		})
 	}
 
 	wg.Wait()