feat: complete feature gaps across all modules

Server:
- Add settings-cache with 60s TTL for feature toggle checks
- Enforce maintenance_mode on login, enable_binding on device bind

Admin console:
- Remove dead "发送通知" button from user detail
- Firmware check calls real API and compares versions

Miniprogram:
- Wear-check: dynamic battery/connected from BLE state
- Login: hide non-functional phone auth button
- Treating: show actual selected regions instead of hardcoded "全脸"
- Index: display subscription status with tap to manage
- Auto-scan: show "待检测" instead of "--" for PD data
- Agreements: tap shows "内容建设中" modal

admin-console/src/views/DeviceDetailView.vue

@@ -162,8 +162,25 @@ export default {
     onViewLogs() {
       this.$emit('navigate', 'log', { device_id: this.deviceId })
     },
-    onCheckUpdate() {
+    async onCheckUpdate() {
       uni.showToast({ title: '正在检查更新...', icon: 'none' })
+      try {
+        const data = await get('/api/v1/admin/firmware')
+        const records = data.records || []
+        const latest = records.filter(r => r.status === 1).sort((a, b) => b.firmware_id - a.firmware_id)[0]
+        if (!latest) {
+          uni.showToast({ title: '暂无固件信息', icon: 'none' })
+          return
+        }
+        const current = this.device && this.device.firmware_version
+        if (current && current === latest.version) {
+          uni.showToast({ title: '当前已是最新版本', icon: 'success' })
+        } else {
+          uni.showToast({ title: '发现新版本 v' + latest.version, icon: 'none', duration: 3000 })
+        }
+      } catch (e) {
+        uni.showToast({ title: '检查更新失败', icon: 'none' })
+      }
     },
     formatDate: formatDateUtil
   }

admin-console/src/views/UserDetailView.vue

@@ -5,7 +5,6 @@
     <view class="page-card" v-if="user">
       <view class="page-header">
         <text class="page-title">👥 用户详情 - {{ user.nickname || user.user_id }}</text>
-        <button class="btn-primary btn-sm">发送通知</button>
       </view>
 
       <view class="user-profile">