fix(zsh): strip control characters from window title

The zsh shell integration was using `${(V)1}` parameter expansion to set
the window title, which converts control characters to their visible
escape sequence representations. This caused commands ending with a
newline to display as `command\n` in the title bar.

Changed to use `${1//[[:cntrl:]]}` which strips control characters
entirely, matching the behavior of the bash integration.

src/shell-integration/zsh/ghostty-integration

@@ -204,8 +204,10 @@ _ghostty_deferred_init() {
       # Enable terminal title changes.
       functions[_ghostty_precmd]+="
           builtin print -rnu $_ghostty_fd \$'\\e]2;'\"\${(%):-%(4~|…/%3~|%~)}\"\$'\\a'"
+      # Strip control characters from the command to avoid displaying escape
+      # sequences like \n in the title.
       functions[_ghostty_preexec]+="
-          builtin print -rnu $_ghostty_fd \$'\\e]2;'\"\${(V)1}\"\$'\\a'"
+          builtin print -rnu $_ghostty_fd \$'\\e]2;'\"\${1//[[:cntrl:]]}\"\$'\\a'"
     fi
 
     if [[ "$GHOSTTY_SHELL_FEATURES" == *"cursor"* ]]; then