feat: 为下拉选择组件添加搜索过滤功能，支持拼音匹配

- 新增 search.ts 搜索工具，支持中文拼音（全拼/首字母）模糊匹配
- 新增 select-search-context.ts，通过 provide/inject 为 radix-vue Select 组件注入搜索能力
- MultiSelect、ModelMultiSelect 组件集成搜索框，选项超过阈值时自动显示
- select-content/select-item 组件支持搜索过滤与空状态提示
- StandaloneKeyFormDialog、UserFormDialog 中手写下拉框替换为复用 MultiSelect 组件
- 引入 pinyin-pro 依赖，按需懒加载

Closes #210

Co-authored-by: AoaoMH <kidxb@vip.qq.com>

frontend/src/components/ui/select-content.vue

@@ -10,7 +10,32 @@
       :align-offset="alignOffset"
     >
       <SelectViewport :class="viewportClass">
+        <div
+          v-if="showSearchInput"
+          class="sticky top-0 z-10 bg-card/95 px-1 pt-1 pb-2 backdrop-blur supports-[backdrop-filter]:bg-card/85"
+        >
+          <div class="relative">
+            <Search
+              class="pointer-events-none absolute left-3 top-1/2 h-3.5 w-3.5 -translate-y-1/2 text-muted-foreground"
+            />
+            <Input
+              ref="searchInputRef"
+              v-model="searchQuery"
+              :placeholder="searchPlaceholder"
+              class="h-9 rounded-xl border-border/60 bg-background/80 pl-9 pr-3 text-sm"
+              @keydown.stop
+            />
+          </div>
+        </div>
+
         <slot />
+
+        <div
+          v-if="showEmptyState"
+          class="px-3 py-2 text-sm text-muted-foreground"
+        >
+          未找到匹配项
+        </div>
       </SelectViewport>
     </SelectContentPrimitive>
   </SelectPortal>
@@ -22,9 +47,25 @@ import {
   SelectPortal,
   SelectViewport,
 } from 'radix-vue'
+import { Search } from 'lucide-vue-next'
+import {
+  computed,
+  inject,
+  nextTick,
+  onMounted,
+  onUnmounted,
+  provide,
+  ref,
+  watch,
+} from 'vue'
+import Input from './input.vue'
 import { cn } from '@/lib/utils'
-import { computed, inject } from 'vue'
 import { DIALOG_CONTEXT_KEY } from './dialog/context'
+import {
+  SELECT_SEARCH_CONTEXT_KEY,
+  type RegisteredSelectItem,
+} from './select-search-context'
+import { matchesSearchQuery, preloadPinyin } from '@/utils/search'
 
 interface Props {
   class?: string
@@ -34,6 +75,9 @@ interface Props {
   align?: 'start' | 'center' | 'end'
   alignOffset?: number
   disablePortal?: boolean
+  searchable?: boolean
+  searchThreshold?: number
+  searchPlaceholder?: string
 }
 
 const props = withDefaults(defineProps<Props>(), {
@@ -44,19 +88,105 @@ const props = withDefaults(defineProps<Props>(), {
   align: undefined,
   alignOffset: undefined,
   disablePortal: false,
+  searchable: true,
+  searchThreshold: 8,
+  searchPlaceholder: '输入关键词搜索...',
 })
 
 const isInsideDialog = inject(DIALOG_CONTEXT_KEY, false)
-const shouldDisablePortal = computed(() => props.disablePortal || isInsideDialog)
+const shouldDisablePortal = computed(
+  () => props.disablePortal || isInsideDialog,
+)
+const searchQuery = ref('')
+const searchInputRef = ref<InstanceType<typeof Input> | null>(null)
+const registeredItems = ref<Record<string, RegisteredSelectItem>>({})
+
+const hiddenValues = computed(() => {
+  const query = searchQuery.value.trim()
+  if (!query) return new Set<string>()
+
+  const hidden = new Set<string>()
+  for (const item of Object.values(registeredItems.value)) {
+    if (!matchesSearchQuery(query, item.value, item.text)) {
+      hidden.add(item.value)
+    }
+  }
+  return hidden
+})
+
+provide(SELECT_SEARCH_CONTEXT_KEY, {
+  searchQuery,
+  hiddenValues,
+  registerItem(id, item) {
+    registeredItems.value = {
+      ...registeredItems.value,
+      [id]: item,
+    }
+  },
+  updateItem(id, item) {
+    const currentItem = registeredItems.value[id]
+    if (!currentItem) {
+      return
+    }
+
+    registeredItems.value = {
+      ...registeredItems.value,
+      [id]: {
+        ...currentItem,
+        ...item,
+      },
+    }
+  },
+  unregisterItem(id) {
+    if (!(id in registeredItems.value)) {
+      return
+    }
+
+    const nextItems = { ...registeredItems.value }
+    delete nextItems[id]
+    registeredItems.value = nextItems
+  },
+})
+
+const itemCount = computed(() => Object.keys(registeredItems.value).length)
+const showSearchInput = computed(
+  () => props.searchable && itemCount.value >= props.searchThreshold,
+)
+const showEmptyState = computed(
+  () =>
+    showSearchInput.value &&
+    searchQuery.value.trim().length > 0 &&
+    hiddenValues.value.size === itemCount.value,
+)
+
+onMounted(() => {
+  if (props.searchable) {
+    preloadPinyin()
+  }
+})
+
+watch(showSearchInput, async (visible) => {
+  if (!visible) {
+    searchQuery.value = ''
+    return
+  }
+
+  await nextTick()
+  searchInputRef.value?.inputRef?.focus()
+})
 
 const contentClass = computed(() =>
   cn(
     'z-[200] max-h-96 min-w-[8rem] overflow-hidden rounded-2xl border border-border bg-card text-foreground shadow-2xl backdrop-blur-xl pointer-events-auto',
     'data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95',
     'data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2',
-    props.class
-  )
+    props.class,
+  ),
 )
 
 const viewportClass = 'p-1 max-h-[var(--radix-select-content-available-height)]'
+
+onUnmounted(() => {
+  searchQuery.value = ''
+})
 </script>