estimate-calibrator

# Estimate Calibrator Replaces single-point guesses with structured three-point estimates: decomposes work into atomic units, estimates best/likely/worst case for each, identifies unknowns and assumptions, calculates aggregate ranges using PERT, and assigns confidence levels with explicit rationale. ## Reference Files | File | Contents | Load When | | ---------------------------------- | ------------------------------------------------------------------------- | ---------------------- | | `references/estimation-methods.md` | PERT formula, three-point estimation, Monte Carlo basics | Always | | `references/unknown-categories.md` | Technical, scope, external, and organizational uncertainty types | Unknown identification | | `references/calibration-tips.md` | Cognitive biases in estimation, historical calibration, buffer strategies | Always | | `references/sizing-heuristics.md` | Common task size patterns, complexity indicators, reference class data | Quick sizing needed | ## Prerequisites - Work item description (feature, task, project) - Decomposed tasks (or use task-decomposer skill first) - Context: team familiarity, tech stack, existing codebase ## Workflow ### Phase 1: Decompose Work If the work item is not already decomposed into atomic units: 1. **Break into tasks** — Each task should be es...