fix: pin ruff to 0.15.11 in CI to match local version

Author: parallelArchitect

.github/workflows/lint.yml

@@ -8,6 +8,6 @@ jobs:
       - uses: actions/setup-python@v5
         with:
           python-version: "3.12"
-      - run: pip install ruff
+      - run: pip install ruff==0.15.11
       - run: ruff check .
       - run: ruff format --check .