feat: initial nuwiki Rust workspace (core, lsp, ls)

crates/nuwiki-ls/src/main.rs

@@ -0,0 +1,6 @@
+//! `nuwiki-ls` — language-server binary. Speaks LSP over stdio.
+
+#[tokio::main]
+async fn main() -> std::io::Result<()> {
+    nuwiki_lsp::run_stdio().await
+}