Fix zle-line-init error when connecting via SSH

Guard zle -N widget registration behind function existence checks,
since oh-my-zsh plugins that define these functions may not be loaded
yet depending on shell init order (e.g. over SSH).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

zsh/themes/adlee.zsh-theme

@@ -125,9 +125,9 @@ autoload -Uz add-zsh-hook
 add-zsh-hook preexec adlee_preexec
 add-zsh-hook precmd adlee_precmd
 
-# Configure ZLE
-zle -N zle-line-init
-zle -N zle-keymap-select
+# Configure ZLE (only register widgets if the functions exist, e.g. from vi-mode plugin)
+(( ${+functions[zle-line-init]} )) && zle -N zle-line-init
+(( ${+functions[zle-keymap-select]} )) && zle -N zle-keymap-select
 
 # Initial prompt build (critical for tmux)
 _adlee_build_prompt