feat(config): read g:vimwiki_list on Neovim too (lazy.nvim drop-in)

The g:vimwiki_* drop-in was Vim-only: the Lua client read only setup()
opts and g:nuwiki_wikis, so swapping the vimwiki plugin for nuwiki under
lazy.nvim left the existing vim.g.vimwiki_list ignored and nuwiki pointed
at the default ~/vimwiki.

Mirror autoload/nuwiki/config.vim on the Lua side: config.lua now owns a
single resolver (M.wikis / M.scalar_globals) that resolves setup() wikis →
g:nuwiki_wikis → g:vimwiki_list (translating path->root, path_html->html_path,
template_*, ext->file_extension, …) and folds the global scalar defaults
(g:vimwiki_* then g:nuwiki_* then explicit setup() values; built-in defaults
excluded). lsp.lua (payload) and wiki_cfg/wiki_list (buffer commands) both
route through it, so the server and <Leader>ww agree on the wikis.

Extends test-global-shorthand (15 checks) with the vimwiki_list drop-in +
buffer-command resolution + native-wins cases. Config-parity goldens and
keymap harnesses green on both clients. README + known-issues updated
(drop-in is now Vim & Neovim).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -679,15 +679,17 @@ match vimwiki. To migrate:
 3. Keep your existing config, or point `wiki_root` / `wikis[i].root` at
    your directory.
 
-**Existing `g:vimwiki_list` config works as-is (Vim).** When you haven't
-configured nuwiki natively (`g:nuwiki_wikis` / `g:nuwiki_*`), the Vim
-client reads your upstream `g:vimwiki_list` and `g:vimwiki_*` globals and
-translates them: each wiki's `path`/`path_html`/`template_*`/`auto_export`
+**Existing `g:vimwiki_list` config works as-is (Vim & Neovim).** When you
+haven't configured nuwiki natively (`g:nuwiki_wikis` / `setup()` / `g:nuwiki_*`),
+both clients read your upstream `g:vimwiki_list` and `g:vimwiki_*` globals and
+translate them: each wiki's `path`/`path_html`/`template_*`/`auto_export`
 plus globals like `toc_header_level`, `html_header_numbering`,
 `html_header_numbering_sym`, `links_space_char`, and `list_margin`.
-Native `g:nuwiki_*` config always takes precedence. (Settings nuwiki
-implements differently — see [`known-issues.md`](./known-issues.md) — are
-ignored.)
+Native config always takes precedence. (Settings nuwiki implements
+differently — see [`known-issues.md`](./known-issues.md) — are ignored.)
+On Neovim with lazy.nvim, swap the `vimwiki` plugin spec for nuwiki and
+call `require('nuwiki').setup()` — your `vim.g.vimwiki_list` is picked up
+unchanged.
 
 Existing pages, diary entries, tags, and templates work without
 modification. The first workspace scan after launch may show an empty