refactor: restructure entire project for human maintainability

Server:
- Add Express framework, replace custom router/request parser
- Create DAO layer (12 files) centralizing all 73 SQL queries
- Rewrite 7 route files as thin Express controllers calling DAOs
- Add SCF-to-Express adapter (lib/serverless.js)
- Add auth middleware (middleware/auth.js)
- Remove dead code from lib/auth.js

Admin console:
- Extract DataTable component (table + pagination)
- Extract ConfirmModal component (modal + form styles)
- Create listMixin for paginated list pages
- Move form styles to common.css for slot compatibility
- Refactor device + subscription pages as examples

Miniprogram:
- Split 734-line BLE monolith into 4 focused modules
  (protocol, connection, commands, barrel index)
- Create API module (utils/api.js) with named functions
- Create page utilities (utils/page.js)
- Refactor index + profile pages to use API module

admin-console/src/components/ConfirmModal.vue

@@ -0,0 +1,58 @@
+<template>
+  <view class="modal-mask" v-if="visible" @click="$emit('close')">
+    <view class="modal-content" @click.stop>
+      <view class="modal-title">{{ title }}</view>
+      <slot></slot>
+      <view class="modal-actions">
+        <button class="btn-default" @click="$emit('close')">取消</button>
+        <button class="btn-primary" @click="$emit('confirm')" :loading="loading">{{ confirmText || '确定' }}</button>
+      </view>
+    </view>
+  </view>
+</template>
+
+<script>
+export default {
+  props: {
+    visible: Boolean,
+    title: String,
+    loading: Boolean,
+    confirmText: String
+  }
+}
+</script>
+
+<style scoped>
+@import '../styles/common.css';
+
+.modal-mask {
+  position: fixed;
+  top: 0; left: 0; right: 0; bottom: 0;
+  background: rgba(0,0,0,0.45);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 1000;
+}
+
+.modal-content {
+  width: 480px;
+  background: #fff;
+  border-radius: 8px;
+  padding: 24px;
+}
+
+.modal-title {
+  font-size: 18px;
+  font-weight: 600;
+  margin-bottom: 20px;
+}
+
+.modal-actions {
+  display: flex;
+  justify-content: flex-end;
+  gap: 8px;
+  margin-top: 20px;
+}
+
+</style>

admin-console/src/components/DataTable.vue

@@ -0,0 +1,57 @@
+<template>
+  <view class="page-card">
+    <slot name="toolbar"></slot>
+    <view class="data-table">
+      <view class="t-header">
+        <view class="t-row">
+          <text
+            v-for="col in columns"
+            :key="col.key"
+            :class="'t-th flex' + (col.flex || 1)"
+          >{{ col.label }}</text>
+        </view>
+      </view>
+      <view class="t-body">
+        <slot name="rows"></slot>
+        <view v-if="records.length === 0" class="empty-row">
+          <text class="empty-text">暂无数据</text>
+        </view>
+      </view>
+    </view>
+    <view class="pagination" v-if="totalPages > 1">
+      <button class="btn-page" :disabled="page <= 1" @click="$emit('page', page - 1)">‹</button>
+      <button class="btn-page active">{{ page }}</button>
+      <button class="btn-page" :disabled="page >= totalPages" @click="$emit('page', page + 1)">›</button>
+      <text class="page-info">共 {{ totalPages }} 页</text>
+    </view>
+  </view>
+</template>
+
+<script>
+export default {
+  props: {
+    columns: { type: Array, required: true },
+    records: { type: Array, default: function () { return [] } },
+    page: { type: Number, default: 1 },
+    totalPages: { type: Number, default: 1 }
+  }
+}
+</script>
+
+<style scoped>
+@import '../styles/common.css';
+
+.empty-row {
+  padding: 40px 0;
+  text-align: center;
+}
+
+.empty-text {
+  color: #999;
+  font-size: 14px;
+}
+
+.pagination {
+  justify-content: flex-end;
+}
+</style>