Add keymap to format whole file with gw

Introduces `<leader>gw` to format the entire buffer using the internal
formatting operator gw. It preserves the current window view (cursor
position and scroll) during the operation.

plugin/mappings.lua

@@ -50,3 +50,10 @@ vim.keymap.set('v', '<leader>rg', ":'<,'>Rg<CR>", opts)
 
 -- Mapping to toggle checkboxes
 vim.keymap.set('n', '<leader><CR>', ':CheckboxToggle<CR>', opts)
+
+-- Format whole file using internal algorithm
+vim.keymap.set('n', '<leader>gw', function()
+  local view = vim.fn.winsaveview()
+  vim.cmd('normal! gggwG')
+  vim.fn.winrestview(view)
+end, { desc = 'Format whole file with gw' })