feat(wm-iot): #30 设备影子服务+OTA固件升级完整实现

- entity: DeviceShadow, OtaFirmware, OtaTask, OtaUpgradeRecord
- service: DeviceShadowService (Redis Hash + TTL 24h, 上报/期望/delta/离线检测/批量查询)
- service: OtaService (固件管理/升级任务创建按批次/进度追踪/结果统计)
- controller: DeviceShadowController /api/iot/shadow/*
- controller: OtaController /api/iot/ota/*
- config: RedisConfig (RedisTemplate JSON序列化)
- SQL DDL: iot_ota_firmware, iot_ota_task, iot_ota_upgrade_record
- test: DeviceShadowServiceTest + OtaServiceTest (mock Redis + mock DB)

wm-iot/pom.xml

@@ -13,5 +13,10 @@
         <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency>
         <dependency><groupId>org.postgresql</groupId><artifactId>postgresql</artifactId></dependency>
         <dependency><groupId>net.postgis</groupId><artifactId>postgis-jdbc</artifactId></dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>