ci: added treefmt workflow to gha and removed from buildbot

Author: c4patino

.github/workflows/treefmt.yml

@@ -0,0 +1,22 @@
+name: Formatting
+
+on:
+  pull_request:
+    paths-ignore:
+      - "**.md"
+      - "**.svg"
+      - ".gitignore"
+      - "LICENSE"
+      - "flake.lock"
+
+jobs:
+  lint:
+    name: treefmt
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v31
+      - name: Run treefmt check
+        run: nix build .#checks.x86_64-linux.treefmt --accept-flake-config

flake/dev/fmt.nix

@@ -7,10 +7,6 @@
   perSystem =
     { config, pkgs, ... }:
     {
-      ci.buildbot = {
-        inherit (config.checks) treefmt;
-      };
-
       treefmt.config = {
         projectRootFile = "flake.nix";
         flakeCheck = true;