fix: pin ruff version to 0.12.7 across all environments

- Pin ruff==0.12.7 in pyproject.toml dev dependencies
- Update CI to use exact ruff version instead of latest
- Add comments explaining version pinning rationale
- Ensures consistent formatting across local, CI, and pre-commit

.github/workflows/build-reusable.yml

@@ -26,9 +26,9 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v4
 
-      - name: Install ruff
+      - name: Install dependencies with ruff
         run: |
-          uv tool install ruff
+          uv pip install --system ruff==0.12.7
 
       - name: Run ruff check
         run: |