ci: safe conda channel removal; fix pre-commit and ruff issues

Author: manikyarathore

.github/workflows/main.yaml

@@ -46,6 +46,16 @@ jobs:
           auto-update-conda: true
           conda-solver: libmamba
 
+      - name: Ensure conda 'defaults' channel not present
+        run: |
+          # Only remove the 'defaults' channel if it exists to avoid CondaKeyError
+          if conda config --show channels | grep -q 'defaults'; then
+            conda config --remove channels defaults
+            echo "Removed 'defaults' channel"
+          else
+            echo "'defaults' channel not present, skipping removal"
+          fi
+
       - name: Install dependencies
         run: |
           poetry check
@@ -69,4 +79,4 @@ jobs:
         if: ${{ github.event_name == 'push' }}
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./build
+          publish_dir: ./build