{
  "iterations": [
    {"version": "v1", "score": 69, "delta": 0, "frozen": false},
    {"version": "v2", "score": 72, "delta": "+3", "frozen": false},
    {"version": "v3", "score": 81, "delta": "+9", "frozen": false},
    {"version": "v4", "score": 85, "delta": "+4", "frozen": false},
    {"version": "v5", "score": 86, "delta": "+1", "frozen": false},
    {"version": "v6", "score": 89, "delta": "+3", "frozen": true},
    {"version": "v7", "score": 90, "delta": "+1", "frozen": true}
  ],
  "final_version": "v7",
  "final_score": 90,
  "total_improvement": "+21 (69→90)",
  "frozen_at": "2026-07-10T15:38:00",
  "freeze_reason": "Kimi 90/100, 达到冻结线. V7修复: xfade过渡 + 字幕颜色/透明度 + Hook密度 + 节奏收紧 + reusable badge.",
  "total_iterations": 7,
  "iteration_history": "v1(69) → v2(72,+3) → v3(81,+9) → v4(85,+4) → v5(86,+1) → v6(89,+3) → v7(90,+1)"
}