Add CI workflow to test Python code.

.github/workflows/python.yml

@@ -0,0 +1,31 @@
+name: Python
+
+on:
+  push:
+  pull_request:
+  # Run automatically every monday
+  schedule:
+    - cron: 1 12 * * 1
+
+jobs:
+  build-and-test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Build and install
+        run: python -m pip install amaranth_stdio luna_soc cynthion/python
+
+      - name: Run unit tests
+        run: |
+          python -m unittest discover -s cynthion/python/tests
+          python -m cynthion.gateware.analyzer.analyzer