v0.26.4

Fixed

• Container image: pre-create /home/newb/.claude/ owned by
  the newb user. When the host bind-mounts
  ~/.claude/.credentials.json into the container, Docker would
  otherwise create the parent directory as root, which blocks
  the SDK from writing /home/newb/.claude/session-env at runtime
  (the agent's per-session scratch dir). Symptom on the prior
  image: all 6 prompts authenticated and ran, but every prompt's
  Bash tool refused to initialise — INSTALL: fail / IMPORT: fail
  on a perfectly good package. Pre-creating the dir at image-build
  time, owned by the right uid, fixes it cleanly. Requires
  rebuilding the runner image.
• GitHub Actions Node 20 deprecation. Bumped pinned action
  versions in test.yml, sync-main.yml, publish-pypi.yml, and
  publish-image.yml so they run on Node 24:
  actions/checkout@v4 → @v6, actions/setup-python@v5 → @v6,
  actions/upload-artifact@v4 → @v7,
  codecov/codecov-action@v4 → @v5. (newb-self-verify.yml was
  already on v6/v7.)