refactor(nav): use exit code 75 to suppress redundant "Press Enter" prompt

- app submenus return 75 on back/exit instead of 0
- index menus capture child exit code and skip pause when rc is 75
- applies to apps (coolify, pterodactyl, uptime-kuma, cloudpanel, proxmox) and tools (server-benchmark, system-infos) indexes

apps/index.sh

@@ -66,17 +66,20 @@ menu_apps() {
         show_prompt
         read -r choice
 
+        child_rc=0
         case $choice in
-            1|01) run_sibling "apps/coolify.sh" ;;
-            2|02) run_sibling "apps/pterodactyl.sh" ;;
-            3|03) run_sibling "apps/uptime-kuma.sh" ;;
-            4|04) run_sibling "apps/cloudpanel.sh" ;;
-            5|05) run_sibling "apps/proxmox.sh" ;;
+            1|01) run_sibling "apps/coolify.sh"; child_rc=$? ;;
+            2|02) run_sibling "apps/pterodactyl.sh"; child_rc=$? ;;
+            3|03) run_sibling "apps/uptime-kuma.sh"; child_rc=$? ;;
+            4|04) run_sibling "apps/cloudpanel.sh"; child_rc=$? ;;
+            5|05) run_sibling "apps/proxmox.sh"; child_rc=$? ;;
             0|00) return ;;
             *) echo -e "${RED}[KO] Invalid protocol. Select 0-5.${NC}"; sleep 1; continue ;;
         esac
 
-        if [ "$choice" != "0" ] && [ "$choice" != "00" ]; then
+        # Exit code 75 from a child means it already paused on its own
+        # (its own "Back" or end-of-run prompt) — skip the redundant prompt.
+        if [ "$child_rc" -ne 75 ]; then
             echo ""
             read -r -p "Press Enter to continue..."
         fi