feat(commands): ChangeSymbolTo -range, GenerateLinks path filter, NuwikiGenerateTags

Closes the three new command gaps from the 2026-05-31 re-audit (all real,
client-side, both clients x Vimwiki/Nuwiki):

- VimwikiChangeSymbolTo / ListChangeSymbolI / NuwikiChangeSymbol are now
  -range -nargs=1 via a new list_change_symbol_range(symbol,l1,l2) helper that
  loops over_range; was -nargs=1 only -> E481 on a visual selection.
  ChangeSymbolInListTo / ChangeSymbolInList stay range-less and keep
  whole_list=true.

- VimwikiGenerateLinks / NuwikiGenerateLinks are now -nargs=?; with an arg the
  client dispatches the existing server command nuwiki.links.generateForPath
  ({path}) for real subtree-scoped link generation, else nuwiki.links.generate.
  Was bare -> E488 on an arg.

- Added NuwikiGenerateTags (Vim + Neovim) mirroring VimwikiGenerateTags, with
  -nargs=? -complete=...tags - closes the :Vimwiki*<->:Nuwiki* alias asymmetry.

Tests: cmd.ChangeSymbolTo_range_sets_marker, cmd.GenerateLinks_accepts_optional_path,
cmd.NuwikiGenerateTags_exists (test-keymaps.lua, 283 pass) +
cmd.VimwikiChangeSymbolTo_accepts_range, cmd.VimwikiGenerateLinks_accepts_path,
cmd.NuwikiGenerateTags_exists (test-keymaps-vim.vim, 272/18/21). fmt clean.

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

development/vimwiki-gap.md

@@ -235,10 +235,8 @@ fix site.
   `NuwikiChangeSymbol`) are now `-range -nargs=1` passing `<line1>,<line2>,
   <q-args>` to a new `list_change_symbol_range(symbol, l1, l2)` helper that
   loops `over_range` (both clients). `ChangeSymbolInListTo`/`InList` stay
-  range-less. **Bonus bug found + fixed:** the Neovim `VimwikiChangeSymbolInListTo`
-  and `NuwikiChangeSymbolInList` defs passed `whole_list=false`, so they changed
-  only the current item instead of the whole list — corrected to `true`. Covered
-  by `cmd.ChangeSymbolTo_range_sets_marker` (`test-keymaps.lua`) +
+  range-less (and correctly keep `whole_list=true`). Covered by
+  `cmd.ChangeSymbolTo_range_sets_marker` (`test-keymaps.lua`) +
   `cmd.VimwikiChangeSymbolTo_accepts_range` (`test-keymaps-vim.vim`).
 - [x] **`VimwikiGenerateLinks` lacks `-nargs=?`** _(new, 2026-05-31 re-audit;
   fixed same day)_ — upstream takes an optional rel-path arg; nuwiki was bare,