Add GitHub Actions CI workflow for automated testing

Configure a continuous integration pipeline to run pytest within a Conda environment on pushes, pull requests to the main branch, and a weekly schedule.

Author: calvinp0

.github/workflows/ci.yml

@@ -0,0 +1,33 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  schedule:
+    - cron: '0 6 * * 1'  # Weekly on Monday at 06:00 UTC
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    defaults:
+      run:
+        shell: bash -l {0}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: conda-incubator/setup-miniconda@v3
+        with:
+          environment-file: environment.yml
+          activate-environment: tst_env
+          miniforge-version: latest
+
+      - name: Run tests
+        env:
+          PYTHONPATH: ${{ github.workspace }}
+        run: |
+          pytest --verbose --tb=short autotst/
+          rm -rf species ts test/species test/ts