feat: add backend linter

.github/workflows/lint.yml

@@ -1,7 +1,8 @@
 name: CI
 on: push
 jobs:
-  eslint:
+  frontend:
+    name: frontend (eslint)
     runs-on: ubuntu-latest
     defaults:
       run:
@@ -15,3 +16,22 @@ jobs:
         run: npm install
       - name: ESLint
         run: npm run lint
+  backend:
+    name: format, lint and type-check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install uv
+        uses: astral-sh/setup-uv@v2
+        with:
+          enable-cache: true
+          cache-dependency-glob: "uv.lock"
+          version: "0.4.10"
+      - name: Set up Python
+        run: uv python install
+      - name: Install dependencies
+        run: uv sync --all-extras --dev
+      - name: Check code formatting
+        run: uvx ruff format --check
+      - name: Lint
+        run: uvx ruff check