ci: Add automated Continuous Integration workflow

.github/workflows/main.yml

@@ -0,0 +1,68 @@
+name: Continuous Integration
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  backend:
+    name: Backend CI
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+          cache: "pip"
+
+      - name: Install system dependencies
+        run: sudo apt-get update && sudo apt-get install -y libcairo2-dev pkg-config
+
+      - name: Install Python dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r backend/requirements.txt -r backend/requirements-dev.txt
+
+      - name: Run linting
+        run: ruff check backend testing/backend
+
+      - name: Run test suite
+        run: pytest testing/backend -q -m "not benchmark"
+
+  frontend:
+    name: Frontend CI
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: frontend
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "20"
+          cache: "npm"
+          cache-dependency-path: frontend/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run linting and type checking
+        run: |
+          npm run typecheck
+          npm run quality
+
+      - name: Run test suite
+        run: npm run test
+
+      - name: Build application
+        run: npm run build