fix(lsp): send g:nuwiki_wikis to the server so per-wiki roots are known

The server received only wiki_root (the parent directory) and had no
knowledge of the per-wiki sub-roots configured in g:nuwiki_wikis / the
setup() wikis list. It therefore resolved all links relative to the
parent root, causing every link in a sub-wiki to appear broken.

Vim path (autoload/nuwiki/lsp.vim):
  s:settings() now includes a 'wikis' key when g:nuwiki_wikis is set,
  so the initialization_options and settings payloads carry the full
  per-wiki config (root, diary_rel_path, file_extension, …).

Lua path (lua/nuwiki/lsp.lua):
  Add resolved_opts() which merges vim.g.nuwiki_wikis into
  config.options.wikis when the user configures via VimL rather than
  setup({wikis=…}). init_options(), server_settings(), and the
  pre-0.11 root_dir_for() fallback all use resolved_opts() so the
  server receives the correct per-wiki roots in every code path.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lua/nuwiki/lsp.lua

@@ -14,25 +14,33 @@ local function command()
   return { install.expected_path() }
 end
 
+-- Merge g:nuwiki_wikis (VimL config) into opts.wikis when the user has not
+-- passed wikis through setup(). This lets users who configure via a .vim
+-- file avoid duplicating the list in their Lua setup() call.
+local function resolved_opts()
+  local opts = config.options
+  if not opts.wikis and vim.g.nuwiki_wikis then
+    opts = vim.tbl_extend('force', opts, { wikis = vim.g.nuwiki_wikis })
+  end
+  return opts
+end
+
 --- `initializationOptions` payload: the server reads it once at
 --- `initialize` time via `Config::from_init_params`. This is what
 --- delivers `wiki_root`/`wikis`/HTML/diary config to Rust.
 local function init_options()
-  return config.options
+  return resolved_opts()
 end
 
 --- `settings` payload: the same shape, but sent via
 --- `workspace/didChangeConfiguration` after startup. Lets the server
 --- pick up config changes without a restart.
 local function server_settings()
-  return {
-    nuwiki = config.options,
-  }
+  return { nuwiki = resolved_opts() }
 end
 
 local function root_dir_for(buf_file)
-  -- Walk up from the buffer until we hit a workspace marker, or fall back
-  -- to the configured wiki_root.
+  -- Walk up from the buffer until we hit a workspace marker.
   local found = vim.fs.find(
     { '.git', '.nuwiki' },
     { upward = true, path = vim.fs.dirname(buf_file) }
@@ -40,7 +48,18 @@ local function root_dir_for(buf_file)
   if found then
     return vim.fs.dirname(found)
   end
-  return vim.fn.expand(config.options.wiki_root)
+  -- For multi-wiki setups, find the wiki whose root contains buf_file.
+  local opts = resolved_opts()
+  if opts.wikis then
+    local buf_norm = vim.fs.normalize(buf_file)
+    for _, w in ipairs(opts.wikis) do
+      local root = vim.fn.expand(w.root or '')
+      if root ~= '' and buf_norm:sub(1, #root) == root then
+        return root
+      end
+    end
+  end
+  return vim.fn.expand(opts.wiki_root or '~/vimwiki')
 end
 
 function M.register()