nixvim: add nvim-ufo for LSP/treesitter folding

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

modules/home/nixvim/keymaps.nix

@@ -59,6 +59,10 @@ in {
     (mk "<leader>gh" "<cmd>DiffviewFileHistory %<CR>" "ファイル履歴")
     (mk "<leader>gq" "<cmd>DiffviewClose<CR>" "差分を閉じる")
 
+    # UFO (folding)
+    (mkRaw "zR" "require('ufo').openAllFolds" "全て展開")
+    (mkRaw "zM" "require('ufo').closeAllFolds" "全て折りたたむ")
+
     # Dropbar
     (mkRaw "<leader>dp" "function() require('dropbar.api').pick() end" "dropbarでナビゲート")
 

modules/home/nixvim/plugins/ui/default.nix

@@ -12,5 +12,6 @@
     ./colorizer.nix
     ./dropbar.nix
     ./scrollbar.nix
+    ./ufo.nix
   ];
 }

modules/home/nixvim/plugins/ui/ufo.nix

@@ -0,0 +1,23 @@
+{ pkgs, ... }: {
+  programs.nixvim = {
+    opts = {
+      foldcolumn = "1";
+      foldlevel = 99;
+      foldlevelstart = 99;
+      foldenable = true;
+    };
+
+    extraPlugins = [
+      pkgs.vimPlugins.nvim-ufo
+      pkgs.vimPlugins.promise-async
+    ];
+
+    extraConfigLua = ''
+      require("ufo").setup({
+        provider_selector = function()
+          return { "treesitter", "indent" }
+        end,
+      })
+    '';
+  };
+}