ci: add GitHub Actions test workflow

Runs pytest on Python 3.11 and 3.12 on push to main and PRs.
Uses uv for fast, reproducible installs.

Author: AgentSIM

.github/workflows/ci.yml

@@ -0,0 +1,31 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: Tests (Python ${{ matrix.python-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.11", "3.12"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: astral-sh/setup-uv@v5
+        with:
+          enable-cache: true
+
+      - run: uv python install ${{ matrix.python-version }}
+
+      - run: uv sync --extra dev --python ${{ matrix.python-version }}
+
+      - run: uv run pytest -v