docs: add home-manager installation instructions to README

README.md

@@ -162,6 +162,41 @@ bulkgen tracks the state of each build in `.bulkgen.state.yaml` (auto-generated,
 - Model name
 - Extra parameters (width, height, etc.)
 
+## Installation with Nix / home-manager
+
+bulkgen provides a Nix flake with a home-manager module. Add the flake as an input and enable the module:
+
+```nix
+# flake.nix
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    home-manager.url = "github:nix-community/home-manager";
+    bulkgen.url = "github:kfickel/bulkgen";  # adjust to your actual repo URL
+  };
+
+  outputs = { nixpkgs, home-manager, bulkgen, ... }: {
+    # ... your existing config, then in homeConfigurations:
+    homeConfigurations."user" = home-manager.lib.homeManagerConfiguration {
+      # ...
+      modules = [
+        bulkgen.homeManagerModules.bulkgen
+        {
+          programs.bulkgen.enable = true;
+        }
+      ];
+    };
+  };
+}
+```
+
+This places the `bulkgen` binary on your `$PATH`. To use a different package build (e.g. from a different system or overlay), set `programs.bulkgen.package`.
+
+The flake also exposes:
+
+- `packages.<system>.bulkgen` — the standalone package, usable without home-manager (e.g. `nix run github:kfickel/bulkgen`)
+- `devShells.<system>.default` — development shell with all dependencies
+
 ## Environment variables
 
 | Variable | Required for |