ci: add GitHub Actions CI workflow

Add comprehensive CI workflow with:
- Style checking (black, flake8)
- Type checking (mypy)
- Spell checking (codespell)
- Unit tests on Python 3.9-3.13 (x86_64 and arm64)
- Wheel building
- Documentation building with mkdocs
- GitHub Pages deployment on tags

Signed-off-by: Ben Copeland <ben.copeland@linaro.org>

Author: bhcopeland

.github/workflows/ci.yml

@@ -0,0 +1,140 @@
+name: CI
+
+on:
+  push:
+    branches: [main, master]
+    tags: ['v*']
+  pull_request:
+    branches: [main, master]
+
+jobs:
+  stylecheck:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - name: Install dependencies
+        run: pip install black flake8 tuxpkg
+      - name: Run stylecheck
+        run: make stylecheck
+
+  typecheck:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - name: Install dependencies
+        run: |
+          pip install -e .
+          pip install -r requirements-dev.txt
+      - name: Run typecheck
+        run: make typecheck
+
+  spellcheck:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - name: Install dependencies
+        run: pip install codespell tuxpkg
+      - name: Run spellcheck
+        run: make spellcheck
+
+  unit-tests:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          pip install -e .
+          pip install -r requirements-dev.txt
+      - name: Run tests
+        run: make test
+
+  unit-tests-arm64:
+    runs-on: ubuntu-24.04-arm
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          pip install -e .
+          pip install -r requirements-dev.txt
+      - name: Run tests
+        run: make test
+
+  build-wheel:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - name: Install flit
+        run: pip install flit
+      - name: Build wheel
+        run: flit build
+      - uses: actions/upload-artifact@v4
+        with:
+          name: wheel
+          path: dist/*.whl
+
+  docs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - name: Install dependencies
+        run: pip install mkdocs-material tuxpkg
+      - name: Build docs
+        run: make doc
+      - uses: actions/upload-artifact@v4
+        with:
+          name: docs
+          path: public
+
+  pages:
+    runs-on: ubuntu-latest
+    needs: docs
+    if: startsWith(github.ref, 'refs/tags/v')
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: docs
+          path: public
+      - name: Setup Pages
+        uses: actions/configure-pages@v4
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: public
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4