feat(device): 无障碍保护存活心跳检测 + 掉线终端告警

- 新增 device 表 + /api/v1/device/{register,heartbeat} + 迁移 device_table
- heartbeat_monitor_worker 周期扫描心跳超时(App 被杀/无障碍停)→ 服务器终端打印告警
  (推送本期未接,先用 logger 终端打印代替真实通知;integrations/jpush.py 已备,后续直接替换)
- config / .env.example 增 JPUSH_* / HEARTBEAT_*
- 见 spec(仓库外 e:\codes\spec\accessibility-liveness-push.md)

注:本提交同时快照了并行 session 未提交的 coupon_state 改动 + 相关 migration
(与本功能同迁移链耦合,无法单独拆分,经确认一并提交)。

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

app/api/v1/device.py

@@ -0,0 +1,66 @@
+"""设备注册 / 心跳 endpoint(无障碍保护存活检测)。
+
+路由前缀 /api/v1/device,需 Bearer 鉴权(设备绑登录用户)。
+  POST /register   注册设备 / 更新 registration_id(App 前台、拿到 push token 时调)
+  POST /heartbeat  上报心跳(无障碍服务存活时周期调,刷新存活)
+
+后端 heartbeat_monitor_worker 据此发现心跳超时的设备并极光推送告警。
+见 spec: spec/accessibility-liveness-push.md。
+"""
+from __future__ import annotations
+
+import logging
+
+from fastapi import APIRouter
+
+from app.api.deps import CurrentUser, DbSession
+from app.repositories import device as device_repo
+from app.schemas.device import (
+    DeviceOut,
+    DeviceRegisterRequest,
+    HeartbeatRequest,
+    OkResponse,
+)
+
+logger = logging.getLogger("shagua.device")
+
+router = APIRouter(prefix="/api/v1/device", tags=["device"])
+
+
+@router.post("/register", response_model=DeviceOut, summary="注册设备/更新推送token")
+def register_device(
+    req: DeviceRegisterRequest,
+    user: CurrentUser,
+    db: DbSession,
+) -> DeviceOut:
+    device = device_repo.register_or_update(
+        db,
+        user_id=user.id,
+        device_id=req.device_id,
+        registration_id=req.registration_id,
+        platform=req.platform,
+        app_version=req.app_version,
+    )
+    logger.info(
+        "device register user_id=%d device_id=%s reg=%s",
+        user.id,
+        req.device_id,
+        bool(req.registration_id),
+    )
+    return DeviceOut.model_validate(device)
+
+
+@router.post("/heartbeat", response_model=OkResponse, summary="上报心跳")
+def report_heartbeat(
+    req: HeartbeatRequest,
+    user: CurrentUser,
+    db: DbSession,
+) -> OkResponse:
+    device_repo.touch_heartbeat(
+        db,
+        user_id=user.id,
+        device_id=req.device_id,
+        accessibility_enabled=req.accessibility_enabled,
+        registration_id=req.registration_id,
+    )
+    return OkResponse()