Enhance dependency installation in CI workflow

Updated the CI workflow to conditionally install dependencies from requirements.txt or requirements.md.

Author: Zhugy-8086

.github/workflows/ci.yml

@@ -7,7 +7,12 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v5
         with: { python-version: '3.12' }
-      - run: pip install -r requirements.txt
+      - name: Install dependencies
+        run: |
+          if [ -f requirements.txt ]; then pip install -r requirements.txt
+          elif [ -f requirements.md ]; then pip install -r requirements.md
+          else echo "No requirements file found — skipping dependency installation"
+          fi
       - run: python verification/validate_math_tree_softmax.py
       - run: python verification/validate_math_vapo_discrete_learning.py
-      - run: python verification/validate_math_tree_softmax_torch.py
+      - run: python verification/validate_math_tree_softmax_torch.py