Set programs.zsh.dotDir to ~/.config/zsh, adopting the new home-manager
default and silencing the dotDir deprecation warning on rebuild. Pin
history.path to the existing ~/.zsh_history so the move doesn't orphan it,
and extend the zcompdump-reset activation to the new $ZDOTDIR location
(legacy $HOME and cache paths still swept). README updated.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>