add ni and svelte language server

modules/development.nix

@@ -11,6 +11,7 @@
       jujutsu
       lazygit
       pnpm
+      ni
 
       # LSPs and formatters (previously via Mason)
       stylua
@@ -18,6 +19,7 @@
       pyright
       vscode-langservers-extracted # includes css-lsp, eslint-lsp, html-lsp, json-lsp
       tailwindcss-language-server
+      svelte-language-server
       biome
       typescript-go