refactor(vim/zsh): update

feat(tmux): add ~/.tmux.local.conf that not managed by git

feat(vim): add github copilot plugin for AI suggestions

Install copilot steps:

1) brew uninstall neovim; brew install --HEAD luajit; brew install --HEAD neovim

2) Start Neovim and invoke `:Copilot setup`

https://copilot.github.com/#faqs