flake.nix: Add impermanence input

Flake lock file updates:

• Added input 'impermanence':
    'github:nix-community/impermanence/4b3e914cdf97a5b536a889e939fb2fd2b043a170?narHash=sha256-LJggUHbpyeDvNagTUrdhe/pRVp4pnS6wVKALS782gRI%3D' (2025-01-25)

flake.lock

@@ -610,6 +610,21 @@
         "type": "github"
       }
     },
+    "impermanence": {
+      "locked": {
+        "lastModified": 1737831083,
+        "narHash": "sha256-LJggUHbpyeDvNagTUrdhe/pRVp4pnS6wVKALS782gRI=",
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "rev": "4b3e914cdf97a5b536a889e939fb2fd2b043a170",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "impermanence",
+        "type": "github"
+      }
+    },
     "ixx": {
       "inputs": {
         "flake-utils": [
@@ -889,6 +904,7 @@
         "firefox-gnome-theme": "firefox-gnome-theme",
         "gitea-github-theme": "gitea-github-theme",
         "home-manager": "home-manager_2",
+        "impermanence": "impermanence",
         "kvlibadwaita": "kvlibadwaita",
         "nixos-hardware": "nixos-hardware",
         "nixos-mailserver": "nixos-mailserver",

flake.nix

@@ -23,6 +23,7 @@
       url = "git+ssh://git@git.vimium.com/jordan/gitea-github-theme.git?ref=main";
       flake = false;
     };
+    impermanence.url = "github:nix-community/impermanence";
     kvlibadwaita = {
       url = "github:GabePoel/KvLibadwaita";
       flake = false;