[bpepple]

Changes

• pyproject.toml: requires-python is now >=3.15, and the ruff and black targets are now py315.
• Containerfile: both the builder and runtime stages now use python:3.15-slim.
• CI: actions/setup-python now installs 3.15.
• uv.lock: relocked for the new minimum. Package versions don't change; the only effect is that the cp314 wheel entries are dropped.

Testing

Run locally against Python 3.15.2:

• pytest --create-db: 2238 passed, 2 skipped (same skips as on 3.14)
• ruff check . and ruff format --check .: clean
• manage.py check: no issues

Deployment / Developer notes

• Production needs an image rebuild to pick up the new base image. I haven't run a container build locally, so the first CI or deploy build will be the first test of python:3.15-slim.
• Local virtualenvs need recreating with uv sync --dev (uv picks up 3.15 from requires-python).