Optimize sleep calls in SSH reachability check

- Only sleep if there's enough time remaining for another check
- Avoid wasting timeout on unnecessary sleeps near the timeout boundary

Co-authored-by: tdgroot <1165302+tdgroot@users.noreply.github.com>

Author: Copilot

src/Brancher/BrancherHypernodeManager.php

@@ -143,7 +143,11 @@ private function checkSshReachability(
                 if ($consecutiveSuccesses >= $reachabilityCheckCount) {
                     return true;
                 }
-                sleep($reachabilityCheckInterval);
+                
+                // Only sleep if there's enough time remaining for another check
+                if ((microtime(true) - $startTime + $reachabilityCheckInterval) < $timeout) {
+                    sleep($reachabilityCheckInterval);
+                }
             } else {
                 if ($consecutiveSuccesses > 0) {
                     $this->log->info(
@@ -156,7 +160,11 @@ private function checkSshReachability(
                     );
                 }
                 $consecutiveSuccesses = 0;
-                sleep($reachabilityCheckInterval);
+                
+                // Only sleep if there's enough time remaining for another check
+                if ((microtime(true) - $startTime + $reachabilityCheckInterval) < $timeout) {
+                    sleep($reachabilityCheckInterval);
+                }
             }
         }