禁止已发放二维码回退待用

frontend/src/features/admin/views/AdminQrCodePoolView.vue

@@ -47,6 +47,7 @@ const editForm = reactive({
   note: '',
   status: 'unused' as QrCodeStatus,
   expires_at: '' as string,
+  was_issued: false,
 })
 
 const statusOptions: { label: string; value: QrCodeStatus | ''; type: string }[] = [
@@ -64,6 +65,12 @@ const statusMap = computed(() => {
   return m
 })
 
+const editStatusOptions = computed(() =>
+  editForm.was_issued
+    ? statusOptions.filter(option => option.value === 'used' || option.value === 'disabled')
+    : statusOptions.filter(option => option.value === 'unused' || option.value === 'disabled')
+)
+
 const maxBatchUploadCount = 20
 const uploading = computed(() => uploadPendingCount.value > 0)
 const uploadBusy = computed(() => uploading.value || uploadSaving.value)
@@ -172,6 +179,7 @@ function openEdit(row: ChatQrCode) {
   editForm.note = row.note
   editForm.status = row.status
   editForm.expires_at = row.expires_at ? row.expires_at.replace('T', ' ').slice(0, 16) : ''
+  editForm.was_issued = row.status === 'used' || Boolean(row.conversation_id || row.used_at)
   editVisible.value = true
 }
 
@@ -451,8 +459,12 @@ onMounted(reloadAll)
         </el-form-item>
         <el-form-item label="状态">
           <el-select v-model="editForm.status" style="width: 100%">
-            <el-option label="待用" value="unused" />
-            <el-option label="已停用" value="disabled" />
+            <el-option
+              v-for="option in editStatusOptions"
+              :key="option.value"
+              :label="option.label"
+              :value="option.value"
+            />
           </el-select>
         </el-form-item>
         <el-form-item label="备注">