Idempotent PostgreSQL migration extracted directly from paperdynasty_dev
on 2026-03-23. Replaces PR #84 which had schema drift.
Creates evolution_track, evolution_card_state, evolution_tier_boost,
evolution_cosmetic, batting_season_stats, pitching_season_stats.
Adds card.variant, battingcard.image_url, pitchingcard.image_url.
All DDL uses CREATE TABLE IF NOT EXISTS and ADD COLUMN IF NOT EXISTS.
Wrapped in a single transaction.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>