fix: 输入框 Enter 键忽略 IME 输入法合字阶段，防止误触提交

中文输入法在选字时按回车，会触发 keydown.enter 事件，
但此时 v-model 尚未更新（组合阶段未结束），导致
inputValue 仍为空字符串，造成 saveToDiary 的 if (!name) return
分支被触发，配方从未保存，「我的配方」中自然看不到。

修复方案：
- 监听 compositionstart / compositionend 事件，
  用 isComposing 标记组合状态
- compositionend 时手动同步 inputValue（确保值最新）
- submitPrompt 检查 e.isComposing || isComposing.value，
  任一为真则跳过提交，等用户真正按下独立 Enter 再确认

Co-Authored-By: YoYo <yoyo@euphon.net>

frontend/src/components/CustomDialog.vue

@@ -8,6 +8,8 @@
         type="text"
         style="width:100%;padding:10px 14px;border:1.5px solid #d4cfc7;border-radius:10px;font-size:14px;margin-bottom:16px;outline:none;font-family:inherit;box-sizing:border-box"
         @keydown.enter="submitPrompt"
+        @compositionstart="isComposing = true"
+        @compositionend="onCompositionEnd"
         ref="promptInput"
       />
       <div class="dialog-btn-row">
@@ -19,11 +21,12 @@
 </template>
 
 <script setup>
-import { ref, watch, nextTick } from 'vue'
+import { ref, watch, nextTick, shallowRef } from 'vue'
 import { dialogState, closeDialog } from '../composables/useDialog'
 
 const inputValue = ref('')
 const promptInput = ref(null)
+const isComposing = shallowRef(false)
 
 watch(() => dialogState.visible, (v) => {
   if (v && dialogState.type === 'prompt') {
@@ -46,7 +49,15 @@ function cancel() {
   else closeDialog(null)
 }
 
-function submitPrompt() {
+function onCompositionEnd(e) {
+  isComposing.value = false
+  // After compositionend, update the model value with the committed text
+  inputValue.value = e.target.value
+}
+
+function submitPrompt(e) {
+  // Ignore Enter during IME composition (e.g. Chinese input method confirming a character)
+  if (e.isComposing || isComposing.value) return
   closeDialog(inputValue.value)
 }
 </script>