feat(system): add sudo-toggle function

Toggles sudo password enforcement on/off by writing or
truncating a NOPASSWD rule in /etc/sudoers.d/nofail-toggle.
Useful for temporarily bypassing FIDO key prompts during
batch admin tasks without permanently weakening sudoers.

functions/sudo-toggle.fish

@@ -0,0 +1,16 @@
+function sudo-toggle --description 'Toggle sudo password requirement on/off'
+    # Check the file size using sudo stat to see if our bypass rule is active
+    set -l file_size (sudo stat -c %s /etc/sudoers.d/nofail-toggle 2>/dev/null)
+    
+    if test -n "$file_size"; and test "$file_size" -gt 0
+        # 1. Toggle is currently OFF (Bypass is active). We want to turn security back ON.
+        # We use 'sudo -k' to clear the execution cache so it locks down instantly.
+        sudo -k truncate -s 0 /etc/sudoers.d/nofail-toggle
+        echo "🔒 Sudo security: ENABLED (FIDO Key required)"
+    else
+        # 2. Toggle is currently ON (Security active). We want to BYPASS it.
+        # We write a high-priority user-specific NOPASSWD rule.
+        echo "$USER ALL=(ALL:ALL) NOPASSWD:ALL" | sudo tee /etc/sudoers.d/nofail-toggle > /dev/null
+        echo "🔓 Sudo security: DISABLED (Bypass active)"
+    end
+end