v0.26.1

Fixed

• Container image: pin claude-agent-sdk==0.1.72 in
  containers/Dockerfile. The previous unbounded floor pulled in
  SDK 0.1.77, which raises Claude Code returned an error result: success on the first prompt — observed via newb-self-verify on
  the freshly-built v0.26.0 image. 0.1.72 (used by the v0.23.0 image)
  was the last known-good. We'll un-pin when upstream confirms the
  fix.