Landed directly on main rather than through a PR, so the image-pins
tripwire (pull_request-only) does not turn this bump's one uv.lock line
into a sandbox rebuild.

The skip is provably empty: `git diff v0.37.7..HEAD` is six files under
src/nethackers/hub (the /recognition view and the website), six under
tests/hub, plus this commit's pyproject version and the matching uv.lock
line. No arena or mutator input moved -- nle-base/Dockerfile,
arena/Dockerfile, Dockerfile.mutator, docker-entrypoint.sh,
src/nethackers/__init__.py, _image_pins.py, image_inputs.py,
src/nethackers/arena/ and src/nethackers/contracts/ are all byte-identical
to v0.37.7. The tripwire itself ran on PR #116 and passed, and no Mutator
image or Sandbox images run fired on the branch. Arena stays pinned to its
existing image; no new verified epoch.

Web/hub-only, so this tags and deploys the hub but gets no GitHub release
-- the CLI is unchanged and PyPI stays at 0.37.6.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>