chore: add CI

.gitea/workflows/ci.yaml

@@ -0,0 +1,22 @@
+name: CI
+on:
+  pull_request:
+  push:
+
+concurrency:
+  group: ${{ gitea.workflow }}-${{ gitea.ref }}
+  cancel-in-progress: ${{gitea.ref != 'ref/heads/master' }}
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v31.4.0
+        with:
+          nix_path: nixpkgs=channl:nixos-unstable
+      - name: Clippy
+        run: nix develop --command -- cargo clippy --all
+      - name: Build
+        run: nix build .