add flatpak support - closes #2

flake.lock

@@ -319,6 +319,21 @@
         "type": "github"
       }
     },
+    "nix-flatpak": {
+      "locked": {
+        "lastModified": 1732304879,
+        "narHash": "sha256-/DOW8VadE//HA6tuV2++NowYWi7Wa/FmJHXRJoTQnfQ=",
+        "owner": "gmodena",
+        "repo": "nix-flatpak",
+        "rev": "c84579946c03c996916be0fb6e1340f444c277af",
+        "type": "github"
+      },
+      "original": {
+        "owner": "gmodena",
+        "repo": "nix-flatpak",
+        "type": "github"
+      }
+    },
     "nix-pre-commit": {
       "inputs": {
         "flake-utils": "flake-utils",
@@ -505,6 +520,7 @@
         "catppuccin-vsc": "catppuccin-vsc",
         "compose2nix": "compose2nix",
         "home-manager": "home-manager",
+        "nix-flatpak": "nix-flatpak",
         "nix-vscode-extensions": "nix-vscode-extensions",
         "nixpkgs": "nixpkgs_3",
         "nixvim": "nixvim",