Skill: Update Plan

What This Skill Does

Keeps planning artifacts synchronized with actual progress:

• Updates todo items (mark done, add new items, note blockers)
• Updates phase status (pending → in_progress → completed)
• Updates plan status and changelog
• Updates implementation plan if approach changed during work
• Prepares for next phase when current phase completes

When to Use

• During work on a plan phase: to track progress in real-time
• After completing work: to mark items and phases as done
• When blockers are discovered: to document them
• When the implementation approach changes: to update the implementation plan
• When the user asks to "update the plan" or "mark phase as done"