docs(readme): clarify this is the server; the plugin lives at gffranco/nuwiki

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -1,6 +1,14 @@
 # nuwiki-rs
 
-Rust crates powering [nuwiki](https://code.gfran.co/gffranco/nuwiki): the vimwiki-compatible language server and editor plugin for Vim/Neovim.
+The Rust language server (`nuwiki-ls`) behind [nuwiki](https://code.gfran.co/gffranco/nuwiki), the vimwiki-compatible Vim/Neovim plugin.
+
+> [!NOTE]
+> **This repo is the server only.** If you just want to *use* nuwiki in
+> Vim/Neovim, install the plugin from
+> **[gffranco/nuwiki](https://code.gfran.co/gffranco/nuwiki)** — it downloads
+> a prebuilt `nuwiki-ls` binary from this repo's releases automatically, so
+> you don't need this repo or a Rust toolchain. Work here only to develop the
+> parser / LSP / HTML renderer.
 
 ## Crates