fix: 搜索过滤收藏、拼音首字母匹配、清除图片、滑动切换、通知已读

1. 搜索时收藏配方也按关键词过滤，不匹配的隐藏
2. 编辑配方添加精油时支持拼音首字母匹配（如xyc→薰衣草）
3. 品牌设置页清除图片立即保存到后端，不需点保存按钮
4. 左右滑动切换tab，轮播区域内滑动切换图片不触发tab切换
5. 通知列表每条未读通知加"已读"按钮，调用POST /api/notifications/{id}/read

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/App.vue

@@ -39,7 +39,7 @@
   </div>
 
   <!-- Main content -->
-  <div class="main">
+  <div class="main" @touchstart="onSwipeStart" @touchend="onSwipeEnd">
     <router-view />
   </div>
 
@@ -54,7 +54,7 @@
 </template>
 
 <script setup>
-import { ref, onMounted, watch } from 'vue'
+import { ref, computed, onMounted, watch } from 'vue'
 import { useRouter, useRoute } from 'vue-router'
 import { useAuthStore } from './stores/auth'
 import { useOilsStore } from './stores/oils'
@@ -106,6 +106,48 @@ function toggleUserMenu() {
   showUserMenu.value = !showUserMenu.value
 }
 
+// Swipe to switch tabs
+const swipeStartX = ref(0)
+const swipeStartY = ref(0)
+
+// Tab order for swipe navigation (only user-accessible tabs)
+const tabOrder = computed(() => {
+  const tabs = ['search', 'oils']
+  if (auth.isLoggedIn) {
+    tabs.splice(1, 0, 'manage', 'inventory')
+  }
+  if (auth.isBusiness) tabs.push('projects')
+  return tabs
+})
+
+function onSwipeStart(e) {
+  const touch = e.touches[0]
+  swipeStartX.value = touch.clientX
+  swipeStartY.value = touch.clientY
+}
+
+function onSwipeEnd(e) {
+  const touch = e.changedTouches[0]
+  const dx = touch.clientX - swipeStartX.value
+  const dy = touch.clientY - swipeStartY.value
+  // Only trigger if horizontal swipe is dominant and > 50px
+  if (Math.abs(dx) < 50 || Math.abs(dy) > Math.abs(dx)) return
+  // Check if the swipe originated inside a carousel (data-no-tab-swipe)
+  if (e.target.closest && e.target.closest('[data-no-tab-swipe]')) return
+
+  const tabs = tabOrder.value
+  const currentIdx = tabs.indexOf(ui.currentSection)
+  if (currentIdx < 0) return
+
+  if (dx < -50 && currentIdx < tabs.length - 1) {
+    // Swipe left -> next tab
+    goSection(tabs[currentIdx + 1])
+  } else if (dx > 50 && currentIdx > 0) {
+    // Swipe right -> previous tab
+    goSection(tabs[currentIdx - 1])
+  }
+}
+
 onMounted(async () => {
   await auth.initToken()
   await Promise.all([