refactor(health): remove unused duration formatting function

- Remove formatDurationSeconds function that was not being utilized
- Remove unused fmt import from clients.go
- Simplify codebase by eliminating dead code

Author: Rxflex

health/clients.go

@@ -1,7 +1,6 @@
 package health
 
 import (
-	"fmt"
 	"strconv"
 	"time"
 )
@@ -64,20 +63,3 @@ func getActiveClients(portFilter string) []ClientInfo {
 
 	return result
 }
-
-func formatDurationSeconds(d time.Duration) string {
-	d = d.Round(time.Second)
-	h := d / time.Hour
-	d -= h * time.Hour
-	m := d / time.Minute
-	d -= m * time.Minute
-	s := d / time.Second
-
-	if h > 0 {
-		return fmt.Sprintf("%dh%dm%ds", h, m, s)
-	}
-	if m > 0 {
-		return fmt.Sprintf("%dm%ds", m, s)
-	}
-	return fmt.Sprintf("%ds", s)
-}