ci: run ruff and pytest on pushes and pull requests

.github/workflows/ci.yml

@@ -0,0 +1,22 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+          cache: pip
+      # CPU-only torch first, so sentence-transformers does not pull the CUDA wheels.
+      - run: pip install torch --index-url https://download.pytorch.org/whl/cpu
+      - run: pip install -e ".[dev]"
+      - run: ruff check .
+      - run: ruff format --check .
+      - run: pytest -q

DECISIONS.md

@@ -451,3 +451,14 @@ page. What follows is what that left open.
   `TestEdit::test_updates_the_citation` failed. Found while running the suite
   for this feature; fixed in its own commit.
 
+
+## Continuous integration
+
+- **One GitHub Actions job: `ruff check`, `ruff format --check`, `pytest`**, on
+  pushes to `main` and on every pull request. The suite stubs the embedder and
+  generates its own PDFs, so the job downloads no models and needs no secrets.
+- **CI runs Python 3.11, the supported floor.** The development venv is 3.12,
+  so the floor is the version nothing else exercises.
+- **CPU-only `torch` is installed before the package.** On Linux the default
+  wheel bundles CUDA libraries the tests never use; the CPU index keeps the
+  install small.