fix(menu): route every cancel branch through back_to for direct-keybinding consistency

Audit of all show_*_menu functions after the theme/background fix found
11 more cancel branches that called their parent directly instead of
back_to. None are reachable from current keybindings (today's direct
invocations target submenus that already use back_to), so the bug is
latent — but any future `nomarchy-menu <area>` keybinding into one of
these would bounce the user into the parent on Esc instead of exiting
cleanly, the exact bug that prompted the previous commit's fix to
show_theme_menu / show_background_menu.

Mechanical sweep:

  *) show_main_menu   ;;  ->  *) back_to show_main_menu   ;;   (5 sites)
  *) show_setup_menu  ;;  ->  *) back_to show_setup_menu  ;;   (3 sites)
  *) show_update_menu ;;  ->  *) back_to show_update_menu ;;   (3 sites)

Behavior under nested navigation (BACK_TO_EXIT=false) is unchanged:
back_to falls through to calling the parent function by name. Only
direct-invocation cancel paths gain the correct exit-0 behavior.

Action branches and go_to_menu's dispatch table intentionally still use
direct calls — those are forward navigation, not cancel.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

features/scripts/utils/nomarchy-menu

@@ -66,7 +66,7 @@ show_learn_menu() {
   *Arch*) nomarchy-launch-webapp "https://wiki.archlinux.org/title/Main_page" ;;
   *Bash*) nomarchy-launch-webapp "https://devhints.io/bash" ;;
   *Neovim*) nomarchy-launch-webapp "https://www.lazyvim.org/keymaps" ;;
-  *) show_main_menu ;;
+  *) back_to show_main_menu ;;
   esac
 }
 
@@ -76,7 +76,7 @@ show_trigger_menu() {
   *Share*) show_share_menu ;;
   *Toggle*) show_toggle_menu ;;
   *Hardware*) show_hardware_menu ;;
-  *) show_main_menu ;;
+  *) back_to show_main_menu ;;
   esac
 }
 
@@ -173,7 +173,7 @@ show_style_menu() {
   *Hyprland*) open_in_editor ~/.config/hypr/looknfeel.conf ;;
   *Screensaver*) open_in_editor ~/.config/nomarchy/branding/screensaver.txt ;;
   *About*) open_in_editor ~/.config/nomarchy/branding/about.txt ;;
-  *) show_main_menu ;;
+  *) back_to show_main_menu ;;
   esac
 }
 
@@ -214,7 +214,7 @@ show_setup_menu() {
   *DNS*) present_terminal nomarchy-setup-dns ;;
   *Security*) show_setup_security_menu ;;
   *Config*) show_setup_config_menu ;;
-  *) show_main_menu ;;
+  *) back_to show_main_menu ;;
   esac
 }
 
@@ -232,7 +232,7 @@ show_setup_security_menu() {
   case $(menu "Setup" "󰈷  Fingerprint\n  Fido2") in
   *Fingerprint*) present_terminal nomarchy-setup-fingerprint ;;
   *Fido2*) present_terminal nomarchy-setup-fido2 ;;
-  *) show_setup_menu ;;
+  *) back_to show_setup_menu ;;
   esac
 }
 
@@ -248,7 +248,7 @@ show_setup_config_menu() {
   *Waybar*) open_in_editor ~/.config/waybar/config.jsonc && nomarchy-restart-waybar ;;
   *XCompose*) open_in_editor ~/.XCompose && nomarchy-restart-xcompose ;;
   *Overrides*) xdg-open ~/.config/nomarchy/overrides/ ;;
-  *) show_setup_menu ;;
+  *) back_to show_setup_menu ;;
   esac
 }
 
@@ -271,7 +271,7 @@ show_setup_system_menu() {
   *Suspend*) nomarchy-toggle-suspend ;;
   *"Enable Hibernate"*) present_terminal nomarchy-hibernation-setup ;;
   *"Disable Hibernate"*) present_terminal nomarchy-hibernation-remove ;;
-  *) show_setup_menu ;;
+  *) back_to show_setup_menu ;;
   esac
 }
 
@@ -287,7 +287,7 @@ show_update_menu() {
   *Timezone*) present_terminal nomarchy-tz-select ;;
   *Time*) present_terminal nomarchy-update-time ;;
   *Password*) show_update_password_menu ;;
-  *) show_main_menu ;;
+  *) back_to show_main_menu ;;
   esac
 }
 show_update_process_menu() {
@@ -297,7 +297,7 @@ show_update_process_menu() {
   *Swayosd*) nomarchy-restart-swayosd ;;
   *Walker*) nomarchy-restart-walker ;;
   *Waybar*) nomarchy-restart-waybar ;;
-  *) show_update_menu ;;
+  *) back_to show_update_menu ;;
   esac
 }
 
@@ -308,7 +308,7 @@ show_update_hardware_menu() {
   *Audio*) present_terminal nomarchy-restart-pipewire ;;
   *Wi-Fi*) present_terminal nomarchy-restart-wifi ;;
   *Bluetooth*) present_terminal nomarchy-restart-bluetooth ;;
-  *) show_update_menu ;;
+  *) back_to show_update_menu ;;
   esac
 }
 
@@ -316,7 +316,7 @@ show_update_password_menu() {
   case $(menu "Update Password" "  Drive Encryption\n  User") in
   *Drive*) present_terminal nomarchy-drive-set-password ;;
   *User*) present_terminal passwd ;;
-  *) show_update_menu ;;
+  *) back_to show_update_menu ;;
   esac
 }