feat(internal): 启动确认窗 agent 兜底样本落盘(pricebot 回写)

- 新增内部端点 POST /internal/launch-confirm-sample(X-Internal-Secret 鉴权):
  pricebot 对没见过文案的启动确认窗用 LLM 兜底放行后,把样本(host 包 / 弹窗树 /
  LLM plan / 设备 locale 机型)回写落 launch_confirm_sample 表,供研发人工沉淀回
  pricebot 规则 yaml
- 配套: model LaunchConfirmSample + schema + repo(都上报不去重) + alembic 迁移
  launch_confirm_sample_table(down_revision=cps_wx_user) + main 注册 router +
  models/__init__ 登记
- docs: 后端技术实现.md 加 §6.5 pricebot 回写内部端点说明

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/main.py

@@ -22,6 +22,7 @@ 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.cps_redirect import router as cps_redirect_router
 from app.api.internal.app_version import router as internal_app_version_router
+from app.api.internal.launch_confirm import router as internal_launch_confirm_router
 from app.api.internal.price import router as internal_price_router
 from app.api.internal.store import router as internal_store_router
 from app.api.v1.feedback import router as feedback_router
@@ -109,6 +110,7 @@ app.include_router(report_router)
 app.include_router(internal_price_router)
 app.include_router(internal_store_router)
 app.include_router(internal_app_version_router)
+app.include_router(internal_launch_confirm_router)
 app.include_router(platform_router)
 # CPS 群发短链跳转 /c/{code}(公网无鉴权:记点击 → 302 跳美团)
 app.include_router(cps_redirect_router)