ci: add monthly Python 3.15 dependency canary

.github/workflows/python315-canary.yml

@@ -0,0 +1,53 @@
+name: Python 3.15 dependency canary
+
+on:
+  schedule:
+    - cron: "17 9 1 * *"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: python315-dependency-canary
+  cancel-in-progress: true
+
+jobs:
+  core-dependencies:
+    name: Core dependency probe on Python 3.15
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    timeout-minutes: 15
+
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - name: Install Python 3.15
+        uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v7.0.0
+        with:
+          python-version: "3.15"
+          allow-prereleases: true
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@bec219d24cd3e171d82865faccec33120bb574f4 # v10.1.0
+        with:
+          version: "0.10.9"
+          enable-cache: true
+
+      - name: Extract current core dependency requirements
+        run: >-
+          python -c 'import tomllib; from pathlib import Path;
+          data = tomllib.loads(Path("pyproject.toml").read_text());
+          Path("python315-core.txt").write_text("\n".join(data["project"]["dependencies"]) + "\n")'
+
+      - name: Run the focused source canary
+        env:
+          PYTHONPATH: src
+        run: >-
+          uv run --isolated --no-project --python 3.15
+          --with-requirements python315-core.txt
+          --with pytest --with pytest-asyncio --with pytest-timeout
+          pytest tests/test_core_abstractions.py tests/test_storage_paths.py
+          tests/test_aqr_provider.py -q