feat(commands): VimwikiTable -nargs=* + Index/TabIndex -count=0 (P3 parity)

Two command-attribute parity fixes (audited against upstream vimwiki master):

- VimwikiTable / NuwikiTable were -nargs=1 and called table_insert() with no
  args, so `:VimwikiTable 4 3` raised E488 and cols/rows were unreachable.
  All four defs (Vim+Neovim × Vimwiki+Nuwiki) are now -nargs=* and forward
  <f-args>; the backing table_insert already parsed cols (a:1) + rows (a:2).

- VimwikiIndex/TabIndex (and Nuwiki forms) switch from bare -count to
  upstream's -count=0. Behavior is unchanged (both default count to 0;
  wiki_index already maps a count to the 1-indexed wiki number) — this just
  matches the upstream declaration exactly.

Tests: cmd.VimwikiTable_passes_cols_and_rows (test-keymaps.lua — asserts a
4-col/3-row table) and cmd.VimwikiTable_accepts_cols_rows (test-keymaps-vim.vim
— no E488). gap doc updated.

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

development/vimwiki-gap.md

@@ -177,7 +177,12 @@ fix site.
 - [ ] `VimwikiReturn` — no Ex-command (mapping-driven only). _Fix:_ `ftplugin/vimwiki.vim`.
 - [ ] `VimwikiTableAlignQ` vs `AlignW` collapsed to one `table_align` — `gqq`
   (align) vs `gww` (align w/o resize) distinction lost.
-- [ ] `VimwikiTable` is `-nargs=1` vs upstream `-nargs=*` (can't pass cols+rows).
+- [x] `VimwikiTable` was `-nargs=1` vs upstream `-nargs=*` (couldn't pass
+  cols+rows). _Fix:_ all four defs (Vim+Neovim × Vimwiki+Nuwiki) are now
+  `-nargs=*` and forward `<f-args>` to `table_insert` (which already parsed
+  cols/rows). Covered by `cmd.VimwikiTable_passes_cols_and_rows`
+  (`test-keymaps.lua`, asserts a `:VimwikiTable 4 3` → 4-col, 3-row table) and
+  `cmd.VimwikiTable_accepts_cols_rows` (`test-keymaps-vim.vim`, no E488).
 - [ ] `VimwikiListChangeLvl` is `-nargs=?` vs upstream `-range -nargs=+`.
 - [x] `VimwikiRebuildTags` `-bang` ("rebuild all") — `:…RebuildTags!` now passes
   `{ all: true }`; the server (`tags_rebuild`) re-indexes **every** configured
@@ -235,9 +240,12 @@ fix site.
 - [ ] **Diary-note family lacks `-count`** _(new, 2026-05-31 re-audit)_ — upstream's
   `:Vimwiki{Make,TabMake,MakeYesterday,MakeTomorrow}DiaryNote` carry `-count=0`
   (the count selects the wiki number); nuwiki's diary-note commands declare no
-  count in either branch, and `Index`/`TabIndex` use bare `-count` vs upstream
-  `-count=0`. _Fix:_ `ftplugin/vimwiki.vim` diary block (both branches) + thread
-  the count into `diary_today/yesterday/tomorrow`.
+  count in either branch. _Fix:_ `ftplugin/vimwiki.vim` diary block (both
+  branches) + thread the count into `diary_today/yesterday/tomorrow` + server
+  diary commands (accept an optional `wiki` selector). _(The `Index`/`TabIndex`
+  half is done: all four defs now use upstream's `-count=0` instead of bare
+  `-count`; `wiki_index`/`wiki_tab_index` already map the count to the wiki
+  number.)_
 - [ ] **No `-complete=` specs** _(new)_ — upstream attaches command-line completion
   to `VimwikiGoto` (links), `VimwikiRenameFile` (files), `VimwikiColorize`
   (colours), and the tag commands. nuwiki defines none, so `<Tab>` completion of