feat(compare): 比价记录落库 + 战绩里程碑(真发金币)

- comparison_record 表 + 上报(幂等 user+trace)/列表/详情 接口;服务端派生
  best/saved/is_source_best/status + information(done 帧文案/失败具体原因)
- 战绩里程碑:comparison_milestone_claim 表 + 进度/领取接口,按成功比价次数
  解锁,复用 grant_coins 真发金币(RECORD_MILESTONES 120/180/300/500/800/1200)
- 迁移 record/information/milestone 三个,单 head;rewards.py 集中档位配置
- 测试 test_compare_record(8)+test_compare_milestone(7) 全绿;docs/api 12a-12e + 索引

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/main.py

@@ -17,6 +17,8 @@ from fastapi.staticfiles import StaticFiles
 from app.api.v1.ad import router as ad_router
 from app.api.v1.auth import router as auth_router
 from app.api.v1.compare import router as compare_router
+from app.api.v1.compare_milestone import router as compare_milestone_router
+from app.api.v1.compare_record import router as compare_record_router
 from app.api.v1.coupon import router as coupon_router
 from app.api.v1.feedback import router as feedback_router
 from app.api.v1.meituan import router as meituan_router
@@ -74,6 +76,8 @@ app.include_router(user_router)
 app.include_router(feedback_router)
 app.include_router(coupon_router)
 app.include_router(compare_router)
+app.include_router(compare_record_router)
+app.include_router(compare_milestone_router)
 app.include_router(meituan_router)
 app.include_router(wallet_router)
 app.include_router(signin_router)