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>

ftplugin/vimwiki.vim

@@ -37,6 +37,33 @@ augroup END
 call nuwiki#colors#refresh()
 let b:undo_ftplugin .= ' | execute "autocmd! NuwikiColorConceal * <buffer>"'
 
+" vimwiki `autowriteall` / `table_auto_fmt` (Vim path; Neovim wires both via
+" lua/nuwiki/ftplugin.lua). autowriteall mirrors the option into Vim's global
+" &autowriteall while a wiki buffer is current (auto-save on switch/make),
+" restoring the prior value on leave. table_auto_fmt re-aligns the table under
+" the cursor on InsertLeave. Disable with g:nuwiki_autowriteall /
+" g:nuwiki_table_auto_fmt = 0.
+if !has('nvim')
+  if get(g:, 'nuwiki_autowriteall', 1)
+    augroup NuwikiAutoWriteAll
+      autocmd! * <buffer>
+      autocmd BufEnter <buffer> let s:nuwiki_awa_saved = &autowriteall | let &autowriteall = 1
+      autocmd BufLeave <buffer> let &autowriteall = get(s:, 'nuwiki_awa_saved', &autowriteall)
+    augroup END
+    " FileType fires after the initial BufEnter, so apply once now too.
+    let s:nuwiki_awa_saved = &autowriteall
+    let &autowriteall = 1
+    let b:undo_ftplugin .= ' | execute "autocmd! NuwikiAutoWriteAll * <buffer>"'
+  endif
+  if get(g:, 'nuwiki_table_auto_fmt', 1)
+    augroup NuwikiTableAutoFmt
+      autocmd! * <buffer>
+      autocmd InsertLeave <buffer> if getline('.') =~# '|' | call nuwiki#commands#table_align() | endif
+    augroup END
+    let b:undo_ftplugin .= ' | execute "autocmd! NuwikiTableAutoFmt * <buffer>"'
+  endif
+endif
+
 if !has('nvim')
   " ===== Plain Vim path =====
   "
@@ -69,7 +96,7 @@ if !has('nvim')
   command! -buffer        VimwikiBaddLink               call nuwiki#commands#badd_link()
   command! -buffer -nargs=* VimwikiSearch  lvimgrep /<args>/ **
   command! -buffer -nargs=* VWS           lvimgrep /<args>/ **
-  command! -buffer -nargs=1 -complete=customlist,nuwiki#complete#pages VimwikiGoto   call nuwiki#commands#wiki_goto_page(<q-args>)
+  command! -buffer -nargs=* -complete=customlist,nuwiki#complete#pages VimwikiGoto   call nuwiki#commands#wiki_goto_page(<q-args>)
 
   command! -buffer        VimwikiDeleteFile    call nuwiki#commands#delete_file()
   command! -buffer        VimwikiDeleteLink    call nuwiki#commands#delete_file()
@@ -152,7 +179,7 @@ if !has('nvim')
   command! -buffer -nargs=? -complete=customlist,nuwiki#complete#tags NuwikiSearchTags         call nuwiki#commands#tags_search(<q-args>)
   command! -buffer -nargs=? -complete=customlist,nuwiki#complete#tags NuwikiGenerateTagLinks   call nuwiki#commands#tags_generate_links(<q-args>)
   command! -buffer -nargs=? -complete=customlist,nuwiki#complete#tags NuwikiGenerateTags       call nuwiki#commands#tags_generate_links(<q-args>)
-  command! -buffer -nargs=1 -complete=customlist,nuwiki#complete#pages NuwikiGoto               call nuwiki#commands#wiki_goto_page(<q-args>)
+  command! -buffer -nargs=* -complete=customlist,nuwiki#complete#pages NuwikiGoto               call nuwiki#commands#wiki_goto_page(<q-args>)
 
   " Canonical :Nuwiki* names that mirror the documented surface.
   " The older :Nuwiki* spellings above stay defined for back-compat.
@@ -417,7 +444,7 @@ command! -buffer        VimwikiTabDropLink lua require('nuwiki.commands').follow
 command! -buffer        VimwikiNextLink    lua require('nuwiki.commands').link_next()
 command! -buffer        VimwikiPrevLink    lua require('nuwiki.commands').link_prev()
 command! -buffer        VimwikiBaddLink    lua require('nuwiki.commands').badd_link()
-command! -buffer -nargs=1 -complete=customlist,nuwiki#complete#pages VimwikiGoto       lua require('nuwiki.commands').wiki_goto_page(<q-args>)
+command! -buffer -nargs=* -complete=customlist,nuwiki#complete#pages VimwikiGoto       lua require('nuwiki.commands').wiki_goto_page(<q-args>)
 command! -buffer        VimwikiBacklinks   lua vim.lsp.buf.references()
 command! -buffer        VWB                lua vim.lsp.buf.references()
 command! -buffer -nargs=* VimwikiSearch     lvimgrep /<args>/ **
@@ -501,7 +528,7 @@ command! -buffer -bang        NuwikiRebuildTags        lua require('nuwiki.comma
 command! -buffer -nargs=? -complete=customlist,nuwiki#complete#tags NuwikiSearchTags         lua require('nuwiki.commands').tags_search(<q-args>)
 command! -buffer -nargs=? -complete=customlist,nuwiki#complete#tags NuwikiGenerateTagLinks   lua require('nuwiki.commands').tags_generate_links(<q-args>)
 command! -buffer -nargs=? -complete=customlist,nuwiki#complete#tags NuwikiGenerateTags       lua require('nuwiki.commands').tags_generate_links(<q-args>)
-command! -buffer -nargs=1 -complete=customlist,nuwiki#complete#pages NuwikiGoto               lua require('nuwiki.commands').wiki_goto_page(<q-args>)
+command! -buffer -nargs=* -complete=customlist,nuwiki#complete#pages NuwikiGoto               lua require('nuwiki.commands').wiki_goto_page(<q-args>)
 
 " Canonical :Nuwiki* names that mirror the documented surface.
 " The older :Nuwiki* spellings above stay defined for back-compat.