add CLI flags, update README accordingly, add mode 'expand'

flake.lock

@@ -2,7 +2,9 @@
   "nodes": {
     "naersk": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
         "lastModified": 1745925850,
@@ -20,27 +22,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1750215678,
-        "narHash": "sha256-Rc/ytpamXRf6z8UA2SGa4aaWxUXRbX2MAWIu2C8M+ok=",
+        "lastModified": 1750776420,
+        "narHash": "sha256-/CG+w0o0oJ5itVklOoLbdn2dGB0wbZVOoDm4np6w09A=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "5395fb3ab3f97b9b7abca147249fa2e8ed27b192",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs_2": {
-      "locked": {
-        "lastModified": 1750134718,
-        "narHash": "sha256-v263g4GbxXv87hMXMCpjkIxd/viIF7p3JpJrwgKdNiI=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "9e83b64f727c88a7711a2c463a7b16eedb69a84c",
+        "rev": "30a61f056ac492e3b7cdcb69c1e6abdcf00e39cf",
         "type": "github"
       },
       "original": {
@@ -52,7 +38,7 @@
     "root": {
       "inputs": {
         "naersk": "naersk",
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": "nixpkgs"
       }
     }
   },