Dogfood tooling dependency updates

[cbusillo]

Summary

• dogfood the waiting Dependabot tooling updates on top of the v2-clean Launchplane workflow boundary
• bump actions/checkout from v6 to v7 across repo workflows, including the Launchplane deploy workflow added after Dependabot opened Bump the "tooling" group with 2 updates across multiple ecosystems #41
• bump pytest from 9.0.3 to 9.1.1 and refresh uv.lock

Supersedes the stale conflicting Dependabot PR #41 without reintroducing repo-local Launchplane checkout/config-authority wiring.

Validation

• actionlint .github/workflows/tests.yml .github/workflows/launchplane-deploy.yml .github/workflows/publish.yml
• ./scripts/check-lockfile.sh
• uv run pytest -q tests/test_launchplane_deploy_workflow.py --no-cov
• uv run pytest -q
• git diff --check