feat: nixvim refactor

modules/home-manager/programs/nixvim/presets/languages/c.nix

@@ -0,0 +1,25 @@
+{ lib, config, ... }:
+let
+  cfg = config.presets.languages.c;
+in
+{
+  options.presets.languages.c = {
+    enable = lib.mkEnableOption "C/C++";
+  };
+
+  config = lib.mkIf cfg.enable {
+    plugins = {
+      conform-nvim.formattersByFt = {
+        c = [ "clang-format" ];
+        cpp = [ "clang-format" ];
+      };
+      lsp.servers.clangd = {
+        enable = true;
+        cmd = [
+          "clangd"
+          "--offset-encoding=utf-16"
+        ];
+      };
+    };
+  };
+}