[NVIM] Add markdown table and checklist support

render-markdown (tables/checkboxes only), vim-table-mode, prettier via
conform, cell jumps and checkbox toggle.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

nvim/ftplugin/markdown.vim

@@ -0,0 +1,66 @@
+" Table cell jumps without table mode ([| ]| {| }|)
+function! s:CellMaps()
+    nmap <buffer> [<Bar> <Plug>(table-mode-motion-left)
+    nmap <buffer> ]<Bar> <Plug>(table-mode-motion-right)
+    nmap <buffer> {<Bar> <Plug>(table-mode-motion-up)
+    nmap <buffer> }<Bar> <Plug>(table-mode-motion-down)
+endfunction
+call s:CellMaps()
+" Leaving table mode unmaps them, so restore
+augroup markdown_cell_maps
+    autocmd! * <buffer>
+    autocmd User TableModeDisabled if &filetype ==# 'markdown' | call s:CellMaps() | endif
+augroup END
+
+" <Leader>T{h,j,k,l} and <Leader><Arrow> jump one cell
+nmap <buffer> <Leader>Th <Plug>(table-mode-motion-left)
+nmap <buffer> <Leader>Tj <Plug>(table-mode-motion-down)
+nmap <buffer> <Leader>Tk <Plug>(table-mode-motion-up)
+nmap <buffer> <Leader>Tl <Plug>(table-mode-motion-right)
+nmap <buffer> <Leader><Left> <Plug>(table-mode-motion-left)
+nmap <buffer> <Leader><Down> <Plug>(table-mode-motion-down)
+nmap <buffer> <Leader><Up> <Plug>(table-mode-motion-up)
+nmap <buffer> <Leader><Right> <Plug>(table-mode-motion-right)
+
+" <Leader>x toggles a checkbox; adds one to plain lines and list items
+lua << EOF
+local function toggle(lnum)
+    local line = vim.fn.getline(lnum)
+    local indent, marker, state, rest = line:match('^(%s*)([-*+] )%[([ xX])%] ?(.*)$')
+    if not indent then
+        indent, marker, state, rest = line:match('^(%s*)(%d+[.)] )%[([ xX])%] ?(.*)$')
+    end
+    if indent then
+        state = state == ' ' and 'x' or ' '
+    else
+        indent, marker, rest = line:match('^(%s*)([-*+] )(.*)$')
+        if not indent then
+            indent, marker, rest = line:match('^(%s*)(%d+[.)] )(.*)$')
+        end
+        if not indent then
+            indent, rest = line:match('^(%s*)(.*)$')
+            marker = '- '
+        end
+        state = ' '
+    end
+    vim.fn.setline(lnum, indent .. marker .. '[' .. state .. '] ' .. rest)
+end
+vim.keymap.set('n', '<Leader>x', function() toggle(vim.fn.line('.')) end,
+    { buffer = true, desc = 'Toggle checkbox' })
+vim.keymap.set('x', '<Leader>x', function()
+    local a, b = vim.fn.line('v'), vim.fn.line('.')
+    for l = math.min(a, b), math.max(a, b) do toggle(l) end
+    vim.api.nvim_feedkeys(vim.keycode('<Esc>'), 'n', false)
+end, { buffer = true, desc = 'Toggle checkboxes' })
+
+-- Shift+arrows jump cells on table rows, keep their default elsewhere
+for key, dir in pairs({ Left = 'left', Down = 'down', Up = 'up', Right = 'right' }) do
+    vim.keymap.set('n', '<Plug>(md-S-' .. key .. ')', '<S-' .. key .. '>', { buffer = true })
+    vim.keymap.set('n', '<S-' .. key .. '>', function()
+        if vim.fn.getline('.'):match('^%s*|') then
+            return '<Plug>(table-mode-motion-' .. dir .. ')'
+        end
+        return '<Plug>(md-S-' .. key .. ')'
+    end, { buffer = true, expr = true, remap = true, desc = 'Table cell or default' })
+end
+EOF