fix(nvim): stop treesitter parser drift from local site installs

Force nvim-treesitter to avoid startup parser installs and rely on Nix-provided grammars only, preventing stale ~/.local/share/nvim/site/parser .so files from causing query/parser mismatches (e.g. vim "tab" node errors on ":").

modules/editor/vim/vim.nix

@@ -141,6 +141,8 @@ in
           extraPackages = with pkgs; [
             gcc # needed for nvim-treesitter
 
+            tree-sitter
+
             # HTML, CSS, JSON
             vscode-langservers-extracted