fix(parity): fifth-pass re-audit — VimwikiGoto nargs, autowriteall, table_auto_fmt

Closes the actionable fifth-pass findings (gap doc updated):

- VimwikiGoto / NuwikiGoto: -nargs=1 -> -nargs=* in all four defs. Was a
  real bug — `:VimwikiGoto` raised E471, `:VimwikiGoto My Page` raised E488,
  and the handler's empty-arg prompt fallback was unreachable. Both clients
  already prompt on empty, so -nargs=* (keeping -complete=pages) restores
  upstream behavior.

- autowriteall (upstream default ON): while a wiki buffer is current, mirror
  Vim's global 'autowriteall' (auto-save on page switch / :make), restoring
  the prior value on leave. Neovim via ftplugin.lua setup_autowriteall
  (BufEnter/BufLeave) gated by the `autowriteall` setup option; Vim via the
  NuwikiAutoWriteAll augroup gated by g:nuwiki_autowriteall.

- table_auto_fmt (upstream default ON): re-align the table under the cursor
  on InsertLeave. Both clients, gated by `table_auto_fmt` / g:nuwiki_table_auto_fmt,
  guarded on the cursor line containing `|` before the async table_align.

Also logged (no code): VimwikiRenameFile missing -nargs=? (subsumed by the
LSP-rename divergence), table_reduce_last_col, user_htmls, hl_headers/
hl_cb_checked, and a commentstring value-mismatch note. Mappings audit clean.

The Neovim harness disables table_auto_fmt in setup (its async re-align would
perturb the deterministic table-nav keystroke cases); its wiring is verified
on a throwaway scratch buffer instead. Docs (README + doc/nuwiki.txt) updated.
Tests: cmd.VimwikiGoto_accepts_multiword, config.autowriteall_applied,
config.table_auto_fmt_autocmd. Neovim 293, Vim 285/18/21 pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

development/tests/test-keymaps-vim.vim

@@ -692,6 +692,32 @@ call s:record(
       \ 'cmd.search_and_tablealign_nargs',
       \ 'err=' . s:attr_err)
 
+" ===== :VimwikiGoto -nargs=* =====
+" Was -nargs=1, so a page name with a space raised E488 (and the empty-arg
+" prompt fallback was unreachable). Now -nargs=*: a multi-word arg must parse.
+" The goto is an LSP roundtrip (no server here); swallow non-attribute errors.
+let s:goto_err = ''
+try
+  silent! VimwikiGoto My Page
+catch /E471\|E488/
+  let s:goto_err = v:exception
+catch
+  " no-LSP / not-found errors are expected and fine here.
+endtry
+call s:record(
+      \ s:goto_err ==# '' ? 1 : 0,
+      \ 'cmd.VimwikiGoto_accepts_multiword',
+      \ 'err=' . s:goto_err)
+
+" ===== autowriteall / table_auto_fmt (Vim path) =====
+" autowriteall (default on) sets Vim's global &autowriteall on the wiki buffer.
+call s:record(&autowriteall ? 1 : 0, 'config.autowriteall_applied',
+      \ '&autowriteall=' . &autowriteall)
+" table_auto_fmt (default on) registers the NuwikiTableAutoFmt InsertLeave group.
+call s:record(exists('#NuwikiTableAutoFmt#InsertLeave') ? 1 : 0,
+      \ 'config.table_auto_fmt_autocmd',
+      \ exists('#NuwikiTableAutoFmt#InsertLeave') ? '' : 'no InsertLeave autocmd')
+
 " ===== :VimwikiRemoveDone -bang -range =====
 " Upstream is `-range`; nuwiki had `-bang` only, so `:'<,'>VimwikiRemoveDone`
 " raised E481. Now `-bang -range`: a ranged invocation must parse (no E481),