restructure

- users/rin/default.nix -> users/rin.nix
- users/rin/home.nix +-> users/rin.nix
- users/rin/*.nix -> modules/user/*.nix
- users/rin/scripts/ -> scripts/
- hosts/winter/default.nix -> hosts/winter.nix
- hosts/winter/*.nix -> modules/system/*.nix

- modules are dynamically imported as sets for system and user

users/rin/neovim.nix

@@ -1,107 +0,0 @@
-{ config, pkgs, ... }: {
-  programs.neovim = {
-    enable = true;
-    viAlias = true;
-    vimAlias = true;
-    vimdiffAlias = true;
-    package = pkgs.neovim-nightly;
-
-    plugins = with pkgs.vimPlugins; [
-      coc-nvim
-      coc-eslint
-      coc-json
-      coc-rust-analyzer
-      coc-tsserver
-
-      ctrlp-vim
-      lualine-nvim
-      nerdtree
-      tokyonight-nvim
-      vim-nix
-      vim-repeat
-      vim-surround
-
-      (nvim-treesitter.withPlugins (p: with p; [
-        tree-sitter-javascript
-        tree-sitter-nix
-        tree-sitter-rust
-        tree-sitter-toml
-        tree-sitter-typescript
-        tree-sitter-yaml
-      ]))
-    ];
-    withNodeJs = true;
-
-    extraConfig = ''
-      " configuration
-      syntax enable
-      set relativenumber number
-      set cursorline
-      set noswapfile
-      set hlsearch
-      set ignorecase
-      set incsearch
-      set title
-      set clipboard^=unnamed
-      set tabstop=8 softtabstop=0 expandtab shiftwidth=4 smarttab
-      set expandtab
-      let g:yaml_recommended_style=0
-
-      " theming
-      let g:tokyonight_style='night'
-      colorscheme tokyonight
-
-      " using tab for trigger completion
-      function! s:check_back_space() abort
-        let col = col('.') - 1
-        return !col || getline('.')[col - 1]  =~ '\s'
-      endfunction
-
-      inoremap <silent><expr> <Tab>
-            \ pumvisible() ? "\<C-n>" :
-            \ <SID>check_back_space() ? "\<Tab>" :
-            \ coc#refresh()
-
-      inoremap <expr> <cr> pumvisible() ? "\<C-y>" : "\<C-g>u\<CR>"
-      inoremap <silent><expr> <c-space> coc#refresh()
-
-      " various aliases
-      nnoremap <c-h> :NERDTreeToggle
-      nnoremap <leader>rs :source $MYVIMRC<CR>
-      nmap <leader>rn <Plug>(coc-rename)
-      command! -nargs=0 Sw w !doas tee % > /dev/null
-
-      " disable read-only warning
-      au BufEnter * set noro
-
-      " disable empty line tildes
-      set fcs=eob:\ 
-
-      lua <<EOF
-        require('nvim-treesitter.configs').setup {
-          highlight = { enable = true }
-        }
-        require('lualine').setup {
-          options = {
-            theme = 'tokyonight'
-          }
-        }
-      EOF
-    '';
-  };
-  xdg.configFile."nvim/coc-settings.json".text = builtins.toJSON {
-    languageserver = {
-      nix = {
-        command = "rnix-lsp";
-        filetypes = [ "nix" ];
-      };
-    };
-    "eslint.enable" = true;
-    "eslint.options" = {
-      configFile = "./.eslintrc.json";
-    };
-    "rust-analyzer.lens.enable" = false;
-    "rust-analyzer.inlayHints.enable" = false;
-    "rust-analyzer.serverPath" = pkgs.rust-analyzer + "/bin/rust-analyzer";
-  };
-}