<purpose Unified planning skill combining 4-phase planning workflow, plan quality verification, and interactive replanning. Produces IMPL PLAN.md, task JSONs, verification reports, and manages plan lifecycle through session-level artifact updates. Routes by mode (plan | verify | replan) and acts as a pure orchestrator: executes phases, parses outputs, and passes context. </purpose <process 1. Architecture Overview 2. Key Design Principles 1. Pure Orchestrator : SKILL.md routes and coordinates only; execution detail lives in phase files 2. Progressive Phase Loading : Read phase docs ONLY when…