Project Handoff Skill: Cross-Session Project Handoff

Project Handoff is a memory-oriented skill designed to address context loss in long-running projects. It generates a `handoff.md` file in the project directory to persistently record the current state, decision rationale, and known pitfalls (symptom → cause → fix), ensuring seamless continuation across sessions. This skill must be updated immediately at critical points to avoid relying on stale information, should be kept distinct from version control, and requires caution to avoid misleading outdated entries.