feat(config-toggle): add Left/Right arrows for directional value changes

Left/Right now adjust the highlighted value one step along the
OFF ← DEFAULT → ON scale, clamped at the ends (no wrap), complementing
Space which cycles through all states and wraps. Right steps toward ON,
Left toward OFF.

Extract the set/erase side-effect into __config_toggle_apply so Space,
Left, and Right share one implementation of the scope-aware
set -U/-g/-Ue/-eg logic. Update the in-panel keybind hint (now
width-padded via string pad so the border stays aligned) and the help
text and offline docs to cover the new keys.

docs/fish-config.md

@@ -1232,15 +1232,20 @@ Add -i (interactive confirmation) to destructive commands:
       Universal — persists across all sessions (set -U)
       Session   — current shell only (set -g)
 
-    Changes apply immediately on each Space keypress. Always available
+    Changes apply immediately on each value keypress. Always available
     regardless of the __fish_config_opinionated master state.
 
     Navigation:
       ↑ ↓ / j k   Move cursor
-      Space        Cycle: ON → OFF → DEFAULT → ON
+      ← →          Set value directionally: OFF ← DEFAULT → ON (clamped)
+      Space        Cycle through all states: ON → OFF → DEFAULT → ON (wraps)
       Tab          Switch scope (Universal ↔ Session)
       q / Escape   Exit
 
+    Left/Right move one step along the OFF–DEFAULT–ON scale and stop at the
+    ends; Space cycles through every state and wraps around. DEFAULT erases
+    the variable so the master switch / built-in default applies.
+
     Flags:
       --help / -h   Show usage.
 

functions/__config_toggle_apply.fish

@@ -0,0 +1,53 @@
+# Copyright (C) 2026 Rootiest
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# SYNOPSIS
+#   __config_toggle_apply <varname> <scope> <value>
+#
+# DESCRIPTION
+#   Applies a state value to an opinionated-component variable in the given
+#   scope, immediately and persistently. Used by config-toggle's Space (cycle)
+#   and Left/Right (directional) handlers so the set/erase logic lives in one
+#   place. A value of "DEFAULT" erases the variable in that scope so the
+#   master switch / built-in default takes over again.
+#
+#     universal → set -U  (on/off)  /  set -Ue  (DEFAULT)
+#     session   → set -g  (on/off)  /  set -eg  (DEFAULT)
+#
+# ARGUMENTS
+#   varname  Variable name without the $ prefix
+#   scope    "universal" or "session"
+#   value    "on", "off", or "DEFAULT"
+#
+# RETURNS
+#   0  Always
+#
+# EXAMPLE
+#   __config_toggle_apply __fish_config_op_aliases universal off
+#   __config_toggle_apply __fish_config_op_greeting session DEFAULT
+function __config_toggle_apply
+    set -l varname $argv[1]
+    set -l scope   $argv[2]
+    set -l value   $argv[3]
+
+    switch $scope
+        case universal
+            switch $value
+                case on
+                    set -U $varname on
+                case off
+                    set -U $varname off
+                case DEFAULT
+                    set -Ue $varname
+            end
+        case session
+            switch $value
+                case on
+                    set -g $varname on
+                case off
+                    set -g $varname off
+                case DEFAULT
+                    set -eg $varname
+            end
+    end
+end

functions/__config_toggle_draw.fish

@@ -131,8 +131,10 @@ function __config_toggle_draw
     printf '│%s│\n' $HBR
 
     # ── Keybind hint ──────────────────────────────────────
-    printf '│  %s↑↓/jk: move  Space: cycle  Tab: scope  q: quit%s  │\n' \
+    # Padded to the inner width so the right border stays aligned regardless
-        $c_dim $c_reset
+    # of the hint text. string pad is width-aware (arrows count as 1 column).
+    set -l hint " ↑↓ move  ←→ set  Space cycle  Tab scope  q quit"
+    printf '│%s%s%s│\n' $c_dim (string pad -r -w $IW -- $hint) $c_reset
 
     # ── Bottom border ─────────────────────────────────────
     printf '└%s┘\n' $HBR

functions/config-toggle.fish

@@ -44,7 +44,8 @@ function config-toggle --description 'Interactive TUI for toggling opinionated c
                 echo
                 echo "$c_head""Navigation:$c_reset"
                 echo "  $c_flag↑ ↓$c_reset or $c_flag""j k$c_reset    Move cursor up / down"
-                echo "  $c_flag""Space$c_reset         Cycle: ON → OFF → DEFAULT → ON"
+                echo "  $c_flag← →$c_reset           Set value: OFF ← DEFAULT → ON (clamped)"
+                echo "  $c_flag""Space$c_reset         Cycle: ON → OFF → DEFAULT → ON (wraps)"
                 echo "  $c_flag""Tab$c_reset           Switch scope (Universal ↔ Session)"
                 echo "  $c_flag""q$c_reset / $c_flag""Esc$c_reset       Exit"
                 echo
@@ -107,12 +108,12 @@ function config-toggle --description 'Interactive TUI for toggling opinionated c
                 else
                     set cur_scope universal
                 end
-            case space   # Space — cycle and apply immediately
+            case space   # Space — cycle through all states and apply
                 set -l varname $vars[(math $cur_row + 1)]
                 set -l cur_val (__config_toggle_get_val $varname $cur_scope)
-                set -l next_val ""
 
-                # Cycle: on → off → DEFAULT → on
+                # Cycle (wraps): on → off → DEFAULT → on
+                set -l next_val on
                 switch $cur_val
                     case on
                         set next_val off
@@ -121,28 +122,37 @@ function config-toggle --description 'Interactive TUI for toggling opinionated c
                     case '*'   # DEFAULT or any unrecognised
                         set next_val on
                 end
+                __config_toggle_apply $varname $cur_scope $next_val
+            case right   # → step toward ON (clamped, no wrap)
+                set -l varname $vars[(math $cur_row + 1)]
+                set -l cur_val (__config_toggle_get_val $varname $cur_scope)
 
-                # Apply immediately
+                # Order: OFF ← DEFAULT → ON
-                switch $cur_scope
+                set -l next_val on
-                    case universal
+                switch $cur_val
-                        switch $next_val
+                    case off
-                            case on
+                        set next_val DEFAULT
-                                set -U $varname on
+                    case on
-                            case off
+                        set next_val on     # already at the right end
-                                set -U $varname off
+                    case '*'   # DEFAULT or unrecognised
-                            case DEFAULT
+                        set next_val on
-                                set -Ue $varname
-                        end
-                    case session
-                        switch $next_val
-                            case on
-                                set -g $varname on
-                            case off
-                                set -g $varname off
-                            case DEFAULT
-                                set -eg $varname
-                        end
                 end
+                __config_toggle_apply $varname $cur_scope $next_val
+            case left    # ← step toward OFF (clamped, no wrap)
+                set -l varname $vars[(math $cur_row + 1)]
+                set -l cur_val (__config_toggle_get_val $varname $cur_scope)
+
+                # Order: OFF ← DEFAULT → ON
+                set -l next_val off
+                switch $cur_val
+                    case on
+                        set next_val DEFAULT
+                    case off
+                        set next_val off    # already at the left end
+                    case '*'   # DEFAULT or unrecognised
+                        set next_val off
+                end
+                __config_toggle_apply $varname $cur_scope $next_val
             case q Q quit escape
                 break
         end