fix(follow-link): create missing page + wrap word on <CR>

Two missing pieces in the previous "follow creates page" fix:

1. **`wiki_root` never reached the server.** The Lua glue (and the
   Vim autoload glue) was sending the config under `settings` — that
   field is for `workspace/didChangeConfiguration` notifications, not
   for `initialize`. The server's `Config::from_init_params` reads
   `initialization_options`, so `wiki_root` arrived as `None`, the
   `Wiki` aggregate was empty, and `wiki_for_uri` returned `None` →
   `resolve_target_uri` bailed before reaching my synthesise path,
   leaving `<CR>` with "No Location Found".

   Both glues now send the same payload under both keys:
   - `lua/nuwiki/lsp.lua` → adds `init_options = init_options()`
     alongside the existing `settings = …`.
   - `autoload/nuwiki/lsp.vim` → adds `initialization_options` to
     the `lsp#register_server` call.

   The server keeps reading from `initializationOptions` at startup
   *and* honouring `didChangeConfiguration` later (Phase 11 plumbing).

2. **No-wiki fallback in the server.** Even with the glue fix above,
   users who launch nuwiki on an ad-hoc `.wiki` file outside any
   workspace folder would still get an empty `wikis` list. The
   `LinkKind::Wiki` arm now falls back to a new
   `synthesise_page_uri_next_to(source_uri, path)` which builds the
   future page next to the current file. `<CR>` on `[[NewPage]]`
   opens `./NewPage.wiki`, save creates it.

3. **`<CR>` on a plain word now wraps + follows.** Mirrors vimwiki's
   `:VimwikiFollowLink`: when the cursor isn't already inside
   `[[…]]`, the new `nuwiki.commands.follow_link_or_create` /
   `nuwiki#commands#follow_link_or_create` first wraps the word
   under cursor as `[[word]]`, places the cursor inside the link,
   then dispatches `vim.lsp.buf.definition()` /
   `:LspDefinition`. Both editor paths now bind `<CR>` /
   `<S-CR>` / `<C-CR>` / `<C-S-CR>` to this smart variant.

Verified end-to-end:
- `[[NewPage]]` with the rebuilt binary: definition returns
  `file:///tmp/wiki/NewPage.wiki` as a Location, so the editor
  opens an empty buffer for it.
- A bare `MyPage` word becomes `[[MyPage]]` in the buffer before
  the follow request fires.

Total 381 tests still pass; fmt + clippy clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

lua/nuwiki/commands.lua

@@ -95,6 +95,80 @@ local function uri_args()
   return { { uri = buf_uri() } }
 end
 
+-- ===== Smart <CR>: follow or create a link =====
+--
+-- Vimwiki's `:VimwikiFollowLink` is smart: when the cursor sits on a
+-- bare word (not inside `[[…]]`), it wraps the word into a wikilink
+-- before following — so `<CR>` on `Notes` becomes `<CR>` on
+-- `[[Notes]]` and opens a fresh buffer for the page. Match that.
+
+local function cursor_inside_wikilink()
+  local line = vim.api.nvim_get_current_line()
+  local col = vim.api.nvim_win_get_cursor(0)[2] + 1 -- 1-based
+  -- Find the most recent `[[` at or before the cursor, then check
+  -- that no `]]` closes it before the cursor.
+  local open_at
+  local i = 1
+  while i < #line do
+    if line:sub(i, i + 1) == '[[' then
+      open_at = i
+      i = i + 2
+    elseif line:sub(i, i + 1) == ']]' then
+      open_at = nil
+      i = i + 2
+    else
+      i = i + 1
+    end
+    if i > col then break end
+  end
+  return open_at ~= nil
+end
+
+local function wrap_cword_as_wikilink()
+  local cword = vim.fn.expand('<cword>')
+  if cword == '' then return false end
+  -- Replace just this `<cword>` occurrence using `*` (the start of
+  -- the last cursor match) — `ciw[[<C-r>"]]` style, but we do it
+  -- via the API so we don't depend on register state.
+  local row, col = unpack(vim.api.nvim_win_get_cursor(0))
+  local line = vim.api.nvim_get_current_line()
+  -- Locate the word boundaries around cursor (0-based col).
+  local left = col
+  while left > 0 and line:sub(left, left):match('[%w_-]') do
+    left = left - 1
+  end
+  -- `left` now sits one before the word start (or at -1 / col=0 if at start).
+  local start_col = left
+  if line:sub(left + 1, left + 1):match('[%w_-]') then
+    start_col = left
+  else
+    start_col = left + 1
+  end
+  local right = start_col + 1
+  while right <= #line and line:sub(right, right):match('[%w_-]') do
+    right = right + 1
+  end
+  local stop_col = right - 1
+  local word = line:sub(start_col + 1, stop_col)
+  if word == '' then return false end
+  local new_line = line:sub(1, start_col) .. '[[' .. word .. ']]' .. line:sub(stop_col + 1)
+  vim.api.nvim_set_current_line(new_line)
+  -- Put cursor inside the new `[[…]]` so the LSP definition request
+  -- lands on the wikilink.
+  vim.api.nvim_win_set_cursor(0, { row, start_col + 2 })
+  return true
+end
+
+function M.follow_link_or_create()
+  if not cursor_inside_wikilink() then
+    if not wrap_cword_as_wikilink() then
+      -- Not on a word either — fall through to plain definition; the
+      -- LSP will simply do nothing if there's no target.
+    end
+  end
+  vim.lsp.buf.definition()
+end
+
 -- ===== Wiki picker =====
 
 function M.wiki_index(count)