feat: add nix app for testing pterm in isolated neovim

Add `nix run .#test-nvim` app that launches Neovim with pterm
pre-loaded for quick manual verification without manual setup.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ttak0422

flake.nix

@@ -94,6 +94,10 @@
             };
           };
 
+          apps = import ./nix/apps {
+            inherit self' pkgs;
+          };
+
           packages = {
             default = pterm;
             inherit pterm pterm-daemon;
@@ -105,4 +109,4 @@
           };
         };
     };
-}
+}

nix/apps/default.nix

@@ -0,0 +1,29 @@
+{
+  self',
+  pkgs,
+  ...
+}:
+
+let
+  mkNeovimApp = cfg: {
+    type = "app";
+    program = "${
+      with pkgs; wrapNeovimUnstable neovim-unwrapped (neovimUtils.makeNeovimConfig cfg)
+    }/bin/nvim";
+  };
+  readLua = path: ''
+    lua << EOF
+    ${builtins.readFile path}
+    EOF
+  '';
+in
+{
+  test-nvim = mkNeovimApp {
+    plugins = [
+      {
+        plugin = self'.packages.pterm;
+        config = readLua ./nvim/pterm.lua;
+      }
+    ];
+  };
+}

nix/apps/nvim/pterm.lua

@@ -0,0 +1 @@
+require("pterm").setup({})