The plain-Vim ftplugin only exposed a whole-layer
g:nuwiki_no_default_mappings gate, so Vim users could not drop a single
keymap group the way Neovim users can via mappings.<group> = false. Add
g:nuwiki_no_{wiki_prefix,links,lists,headers,table_editing,diary,
html_export,text_objects}_mappings, each wrapping its group block, to
reach parity with lua/nuwiki/keymaps.lua. Cover them with a dedicated
opt-out harness and document them in the README and help file.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
gffranco