chore: format repo using treefmt-nix and nixfmt-rfc-style

treefmt.nix

@@ -0,0 +1,19 @@
+{ pkgs, ... }:
+{
+  projectRootFile = "flake.nix";
+
+  programs = {
+    deadnix = {
+      enable = true;
+      no-lambda-pattern-names = true;
+    };
+    nixfmt = {
+      enable = true;
+      package = pkgs.nixfmt-rfc-style;
+    };
+  };
+
+  settings = {
+    on-unmatched = "info";
+  };
+}