feat: 权限修复、搜索改进、滑动切换、通知badge

权限:
- viewer 不能编辑公共配方（前端+后端双重限制）
- viewer 管理配方页只显示"我的配方"
- 取消 token 链接登录，改为自注册+管理员分配角色
- 用户管理页去掉创建用户和复制链接，禁止设管理员
- 修复改权限 API 路径错误

搜索:
- 模糊匹配+同义词扩展（37组），精确/相似分层
- 精确匹配不搜精油成分（避免"西班牙牛至"污染）
- 所有搜索结果底部加"通知编辑添加"按钮

UI:
- 顶部 tab 栏按用户角色显示，切换时居中滚动
- 左右滑动按 visibleTabs 顺序切换 tab
- 用户名旁红色通知数 badge

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

frontend/src/views/UserManagement.vue

@@ -38,27 +38,7 @@
       </div>
     </div>
 
-    <!-- New User Creation -->
-    <div class="create-section">
-      <h4 class="section-title">➕ 创建新用户</h4>
-      <div class="create-form">
-        <input v-model="newUser.username" class="form-input" placeholder="用户名" />
-        <input v-model="newUser.display_name" class="form-input" placeholder="显示名称" />
-        <input v-model="newUser.password" class="form-input" type="password" placeholder="密码 (留空自动生成)" />
-        <select v-model="newUser.role" class="form-select">
-          <option value="viewer">查看者</option>
-          <option value="editor">编辑</option>
-          <option value="senior_editor">高级编辑</option>
-          <option value="admin">管理员</option>
-        </select>
-        <button class="btn-primary" @click="createUser" :disabled="!newUser.username.trim()">创建</button>
-      </div>
-      <div v-if="createdLink" class="created-link">
-        <span>登录链接:</span>
-        <code>{{ createdLink }}</code>
-        <button class="btn-sm btn-outline" @click="copyLink(createdLink)">复制</button>
-      </div>
-    </div>
+    <!-- User self-registers, admin assigns roles below -->
 
     <!-- Search & Filter -->
     <div class="filter-toolbar">
@@ -100,13 +80,12 @@
             :value="u.role"
             class="role-select"
             @change="changeRole(u, $event.target.value)"
+            :disabled="u.role === 'admin'"
           >
             <option value="viewer">查看者</option>
             <option value="editor">编辑</option>
             <option value="senior_editor">高级编辑</option>
-            <option value="admin">管理员</option>
           </select>
-          <button class="btn-sm btn-outline" @click="copyUserLink(u)" title="复制登录链接">🔗</button>
           <button class="btn-sm btn-delete" @click="removeUser(u)" title="删除用户">🗑️</button>
         </div>
       </div>
@@ -118,7 +97,7 @@
 </template>
 
 <script setup>
-import { ref, computed, reactive, onMounted } from 'vue'
+import { ref, computed, onMounted } from 'vue'
 import { useAuthStore } from '../stores/auth'
 import { useUiStore } from '../stores/ui'
 import { api } from '../composables/useApi'
@@ -132,15 +111,6 @@ const searchQuery = ref('')
 const filterRole = ref('')
 const translations = ref([])
 const businessApps = ref([])
-const createdLink = ref('')
-
-const newUser = reactive({
-  username: '',
-  display_name: '',
-  password: '',
-  role: 'viewer',
-})
-
 const roles = [
   { value: 'admin', label: '管理员' },
   { value: 'senior_editor', label: '高级编辑' },
@@ -206,43 +176,10 @@ async function loadBusinessApps() {
   }
 }
 
-async function createUser() {
-  if (!newUser.username.trim()) return
-  try {
-    const res = await api('/api/users', {
-      method: 'POST',
-      body: JSON.stringify({
-        username: newUser.username.trim(),
-        display_name: newUser.display_name.trim() || newUser.username.trim(),
-        password: newUser.password || undefined,
-        role: newUser.role,
-      }),
-    })
-    if (res.ok) {
-      const data = await res.json()
-      if (data.token) {
-        const baseUrl = window.location.origin
-        createdLink.value = `${baseUrl}/?token=${data.token}`
-      }
-      newUser.username = ''
-      newUser.display_name = ''
-      newUser.password = ''
-      newUser.role = 'viewer'
-      await loadUsers()
-      ui.showToast('用户已创建')
-    } else {
-      const err = await res.json().catch(() => ({}))
-      ui.showToast('创建失败: ' + (err.error || err.message || ''))
-    }
-  } catch {
-    ui.showToast('创建失败')
-  }
-}
-
 async function changeRole(user, newRole) {
   const id = user._id || user.id
   try {
-    const res = await api(`/api/users/${id}/role`, {
+    const res = await api(`/api/users/${id}`, {
       method: 'PUT',
       body: JSON.stringify({ role: newRole }),
     })
@@ -270,30 +207,6 @@ async function removeUser(user) {
   }
 }
 
-async function copyUserLink(user) {
-  try {
-    const id = user._id || user.id
-    const res = await api(`/api/users/${id}/token`)
-    if (res.ok) {
-      const data = await res.json()
-      const link = `${window.location.origin}/?token=${data.token}`
-      await navigator.clipboard.writeText(link)
-      ui.showToast('链接已复制')
-    }
-  } catch {
-    ui.showToast('获取链接失败')
-  }
-}
-
-async function copyLink(link) {
-  try {
-    await navigator.clipboard.writeText(link)
-    ui.showToast('已复制')
-  } catch {
-    ui.showToast('复制失败')
-  }
-}
-
 async function approveTranslation(t) {
   const id = t._id || t.id
   try {