fix: 标签保存+管理功能

- 修复 create_diary 不保存 tags 的问题
- 新建标签后加入全局标签列表，移除后显示在候选区
- 标签筛选区：编辑者可新增标签，管理员可删除标签
- 标签筛选区每个标签旁加×删除按钮（管理员）

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

frontend/src/views/RecipeManager.vue

@@ -54,7 +54,11 @@
           class="tag-chip"
           :class="{ active: selectedTags.includes(tag) }"
           @click="toggleTag(tag)"
-        >{{ tag }}</span>
+        >{{ tag }}<span v-if="auth.isAdmin" class="tag-delete" @click.stop="deleteGlobalTag(tag)">×</span></span>
+        <div v-if="auth.canEdit" class="tag-add-row">
+          <input v-model="globalNewTag" class="tag-add-input" placeholder="新标签..." @keydown.enter="addGlobalTag" />
+          <button class="tag-add-btn" @click="addGlobalTag" :disabled="!globalNewTag.trim()">+</button>
+        </div>
       </div>
     </div>
 
@@ -486,6 +490,38 @@ function filterBySearchAndTags(list) {
 const myFilteredRecipes = computed(() => filterBySearchAndTags(myRecipes.value))
 const publicFilteredRecipes = computed(() => filterBySearchAndTags(publicRecipes.value))
 
+const globalNewTag = ref('')
+
+async function addGlobalTag() {
+  const tag = globalNewTag.value.trim()
+  if (!tag) return
+  try {
+    await api('/api/tags', { method: 'POST', body: JSON.stringify({ name: tag }) })
+    if (!recipeStore.allTags.includes(tag)) {
+      recipeStore.allTags.push(tag)
+      recipeStore.allTags.sort((a, b) => a.localeCompare(b, 'zh'))
+    }
+    globalNewTag.value = ''
+    ui.showToast('标签已添加')
+  } catch {
+    ui.showToast('添加失败')
+  }
+}
+
+async function deleteGlobalTag(tag) {
+  const { showConfirm } = await import('../composables/useDialog')
+  const ok = await showConfirm(`确定删除标签「${tag}」？`)
+  if (!ok) return
+  try {
+    await api(`/api/tags/${encodeURIComponent(tag)}`, { method: 'DELETE' })
+    const idx = recipeStore.allTags.indexOf(tag)
+    if (idx >= 0) recipeStore.allTags.splice(idx, 1)
+    ui.showToast('标签已删除')
+  } catch {
+    ui.showToast('删除失败')
+  }
+}
+
 function toggleTag(tag) {
   const idx = selectedTags.value.indexOf(tag)
   if (idx >= 0) selectedTags.value.splice(idx, 1)
@@ -712,9 +748,15 @@ const formCandidateTags = computed(() =>
 
 function addNewFormTag() {
   const tag = newTagInput.value.trim()
-  if (tag && !formTags.value.includes(tag)) {
+  if (!tag) return
+  if (!formTags.value.includes(tag)) {
     formTags.value.push(tag)
   }
+  // Also add to global tags so it appears in candidates if removed
+  if (!recipeStore.allTags.includes(tag)) {
+    recipeStore.allTags.push(tag)
+    recipeStore.allTags.sort((a, b) => a.localeCompare(b, 'zh'))
+  }
   newTagInput.value = ''
 }
 
@@ -1546,6 +1588,14 @@ watch(() => recipeStore.recipes, () => {
 .drops-sm:focus { border-color: #7ec6a4; }
 .select-sm { padding: 4px 6px; border: 1.5px solid #d4cfc7; border-radius: 6px; font-size: 12px; font-family: inherit; background: #fff; width: auto; }
 .btn-select-active { background: #e8f5e9; color: #2e7d5a; border: 1.5px solid #7ec6a4; border-radius: 10px; padding: 7px 14px; font-size: 13px; cursor: pointer; font-family: inherit; font-weight: 600; }
+.tag-delete { margin-left: 4px; cursor: pointer; font-size: 12px; color: #ccc; }
+.tag-delete:hover { color: #c0392b; }
+.tag-add-row { display: flex; gap: 4px; align-items: center; width: 100%; margin-top: 4px; }
+.tag-add-input { flex: 1; padding: 4px 8px; border: 1px solid #e5e4e7; border-radius: 8px; font-size: 12px; outline: none; font-family: inherit; }
+.tag-add-input:focus { border-color: #7ec6a4; }
+.tag-add-btn { border: none; background: #e8f5e9; color: #4a9d7e; border-radius: 6px; padding: 4px 10px; font-size: 12px; cursor: pointer; font-family: inherit; }
+.tag-add-btn:disabled { opacity: 0.4; }
+
 .export-btn {
   margin-left: auto;
   border: none; background: none; cursor: pointer; font-size: 16px; padding: 4px 6px;