fix: enforce formatters on GitHub Actions

.github/workflows/format-backend.yaml

@@ -25,3 +25,5 @@ jobs:
           pip install yapf
       - name: Format backend
         run: bun run format:backend
+      - name: Check for changes after format
+        run: git diff --exit-code

.github/workflows/format-build-frontend.yaml

@@ -18,5 +18,8 @@ jobs:
         run: bun install
       - name: Format frontend
         run: bun run format
+      - name: Check for changes after format
+        run: git diff --exit-code
       - name: Build frontend
+        if: always()
         run: bun run build