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 × 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/InList stay range-less.
  Bonus: the Neovim VimwikiChangeSymbolInListTo + NuwikiChangeSymbolInList defs
  passed whole_list=false, changing only the current item — corrected to 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>

lua/nuwiki/commands.lua

@@ -395,7 +395,17 @@ end
 -- ===== Generation + workspace =====
 
 M.toc_generate = function() exec('nuwiki.toc.generate', uri_args()) end
-M.links_generate = function() exec('nuwiki.links.generate', uri_args()) end
+-- `:VimwikiGenerateLinks [rel_path]` — optional path scopes the links to a
+-- subtree via the server's generateForPath; no arg = every page.
+M.links_generate = function(path)
+  if path and path ~= '' then
+    local args = uri_args()[1]
+    args.path = path
+    exec('nuwiki.links.generateForPath', { args })
+  else
+    exec('nuwiki.links.generate', uri_args())
+  end
+end
 
 -- range>0 restricts the report to the current buffer's [l1, l2] lines
 -- (`:'<,'>VimwikiCheckLinks`); otherwise the whole workspace.
@@ -574,6 +584,13 @@ function M.list_change_symbol(symbol, whole_list)
   exec('nuwiki.list.changeSymbol', { args })
 end
 
+-- `:[range]VimwikiChangeSymbolTo {sym}` / `:[range]VimwikiListChangeSymbolI {sym}`
+-- — upstream is -range -nargs=1; a range sets the marker on every list item in
+-- the selection (single-item when no range, since l1==l2==cursor line).
+function M.list_change_symbol_range(symbol, l1, l2)
+  over_range(l1, l2, function() M.list_change_symbol(symbol, false) end)
+end
+
 function M.list_change_level(delta, whole_subtree)
   local args = pos_args()[1]
   args.delta = delta