v0.5.1

Fixed

• SimBrief generation works again. v0.5.0 shipped playwright 1.65.0, whose driver needs
  libatomic.so.1, which the python:3.12-slim image lacks, so every Generate failed within
  seconds before the click. Playwright is pinned to 1.64.1, and production ran v0.4.7 again
  until this release.
• turn_status reports cancelled after cancel_trip instead of repeating the withdrawn
  approval_required result and its approve instruction.

Changed

• CI builds the container image and starts the Playwright driver inside it, so a dependency
  that cannot run in the deployed image fails before release.