ci: fail lint-kotlin job on ktlint errors

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: mfazekas

.github/workflows/ci.yml

@@ -34,6 +34,7 @@ jobs:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           reporter: github-pr-review
           ktlint_version: "1.5.0"
+          fail_on_error: true
 
   lint:
     runs-on: ubuntu-latest