Update workflow configuration and replace Altair with Matplotlib for signal visualizations

.forgejo/workflows/serve.yaml

@@ -9,12 +9,12 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Initialize virtual environment
-        run: /usr/bin/python -m venv .env
+        run: /usr/bin/python -m venv .venv
       - name: Install dependencies
-        run: ./.env/bin/pip install mystmd jupyter jupyterlab_myst ipykernel altair pandas
+        run: ./.venv/bin/pip install -r requirements.txt
       - name: Build static HTML
         run: |
-          . .env/bin/activate
+          . .venv/bin/activate
           myst build --execute --html
       - name: Copy files
         run: |