feat: 电子药箱小程序 - 4Tab药品管理

- 电子药箱: 药品库存管理 + 手动录入 + 今日用药打卡
- 药品百科: 搜索 + 分类筛选 + 20种药品静态数据
- 惠教中心: 4条药品使用指南课程
- 我的: 家庭成员信息管理
- 自定义TabBar + navigation-bar组件
- SVG药品分类插图

miniprogram/pages/tab-bar/drug-wiki/index.wxml

@@ -0,0 +1,52 @@
+<view class="page">
+  <navigation-bar title="药品百科" back="{{false}}" color="white" background="#4A90D9" />
+
+  <view class="search-section">
+    <view class="search-box">
+      <view class="search-icon">🔍</view>
+      <input class="search-input" placeholder="搜索药品名称、功效、分类…" value="{{searchText}}" bindinput="onSearchInput" confirm-type="search" />
+      <view class="search-clear" wx:if="{{searchText}}" bindtap="onClearSearch">✕</view>
+    </view>
+  </view>
+
+  <scroll-view scroll-x class="category-scroll" wx:if="{{!searchText}}">
+    <view wx:for="{{categories}}" wx:key="*this" class="cat-chip {{activeCategory === item ? 'active' : ''}}" data-cat="{{item}}" bindtap="onCategoryTap">{{item}}</view>
+  </scroll-view>
+
+  <view class="top-search" wx:if="{{!searchText && activeCategory === '全部'}}">
+    <view class="top-label">🔥 热门搜索</view>
+    <view class="top-tags">
+      <view wx:for="{{topSearches}}" wx:key="*this" class="top-tag" data-kw="{{item}}" bindtap="onTopSearchTap">{{item}}</view>
+    </view>
+  </view>
+
+  <view class="result-bar" wx:if="{{searchText || activeCategory !== '全部'}}">
+    <view class="result-text">{{activeCategory !== '全部' ? activeCategory + ' · ' : ''}}共 {{drugList.length}} 个药品</view>
+  </view>
+
+  <view class="drug-list">
+    <view wx:for="{{drugList}}" wx:key="id" class="drug-card" data-id="{{item.id}}" bindtap="goDetail">
+      <view class="card-icon">
+        <image class="card-img" src="{{item.image}}" mode="aspectFit" />
+      </view>
+      <view class="card-body">
+        <view class="card-name">{{item.name}}</view>
+        <view class="card-generic">{{item.genericName}} · {{item.form}}</view>
+        <view class="card-footer">
+          <view class="card-category">{{item.category}}</view>
+          <view class="card-otc {{item.isOTC ? 'otc' : 'rx'}}">{{item.isOTC ? 'OTC' : 'Rx'}}</view>
+        </view>
+      </view>
+      <view class="card-right">
+        <view class="card-price">{{item.price}}</view>
+        <view class="card-arrow">›</view>
+      </view>
+    </view>
+  </view>
+
+  <view class="empty-state" wx:if="{{drugList.length === 0}}">
+    <view class="empty-icon">🔍</view>
+    <view class="empty-text">没有找到相关药品</view>
+    <view class="empty-desc">试试其他关键词或分类</view>
+  </view>
+</view>