feat: 新增全局错误透传规则功能

支持管理员配置上游错误如何返回给客户端：
- 新增 ErrorPassthroughRule 数据模型和 Ent Schema
- 实现规则的 CRUD API（/admin/error-passthrough-rules）
- 支持按错误码、关键词匹配，支持 any/all 匹配模式
- 支持按平台过滤（anthropic/openai/gemini/antigravity）
- 支持透传或自定义响应状态码和错误消息
- 实现两级缓存（Redis + 本地内存）和多实例同步
- 集成到 gateway_handler 的错误处理流程
- 新增前端管理界面组件
- 新增单元测试覆盖核心匹配逻辑

优化：
- 移除 refreshLocalCache 中的冗余排序（数据库已排序）
- 后端 Validate() 增加匹配条件非空校验

frontend/src/components/admin/ErrorPassthroughRulesModal.vue

@@ -0,0 +1,623 @@
+<template>
+  <BaseDialog
+    :show="show"
+    :title="t('admin.errorPassthrough.title')"
+    width="extra-wide"
+    @close="$emit('close')"
+  >
+    <div class="space-y-4">
+      <!-- Header -->
+      <div class="flex items-center justify-between">
+        <p class="text-sm text-gray-500 dark:text-gray-400">
+          {{ t('admin.errorPassthrough.description') }}
+        </p>
+        <button @click="showCreateModal = true" class="btn btn-primary btn-sm">
+          <Icon name="plus" size="sm" class="mr-1" />
+          {{ t('admin.errorPassthrough.createRule') }}
+        </button>
+      </div>
+
+      <!-- Rules Table -->
+      <div v-if="loading" class="flex items-center justify-center py-8">
+        <Icon name="refresh" size="lg" class="animate-spin text-gray-400" />
+      </div>
+
+      <div v-else-if="rules.length === 0" class="py-8 text-center">
+        <div class="mx-auto mb-4 flex h-12 w-12 items-center justify-center rounded-full bg-gray-100 dark:bg-dark-700">
+          <Icon name="shield" size="lg" class="text-gray-400" />
+        </div>
+        <h4 class="mb-1 text-sm font-medium text-gray-900 dark:text-white">
+          {{ t('admin.errorPassthrough.noRules') }}
+        </h4>
+        <p class="text-sm text-gray-500 dark:text-gray-400">
+          {{ t('admin.errorPassthrough.createFirstRule') }}
+        </p>
+      </div>
+
+      <div v-else class="max-h-96 overflow-auto rounded-lg border border-gray-200 dark:border-dark-600">
+        <table class="min-w-full divide-y divide-gray-200 dark:divide-dark-700">
+          <thead class="sticky top-0 bg-gray-50 dark:bg-dark-700">
+            <tr>
+              <th class="px-3 py-2 text-left text-xs font-medium uppercase text-gray-500 dark:text-gray-400">
+                {{ t('admin.errorPassthrough.columns.priority') }}
+              </th>
+              <th class="px-3 py-2 text-left text-xs font-medium uppercase text-gray-500 dark:text-gray-400">
+                {{ t('admin.errorPassthrough.columns.name') }}
+              </th>
+              <th class="px-3 py-2 text-left text-xs font-medium uppercase text-gray-500 dark:text-gray-400">
+                {{ t('admin.errorPassthrough.columns.conditions') }}
+              </th>
+              <th class="px-3 py-2 text-left text-xs font-medium uppercase text-gray-500 dark:text-gray-400">
+                {{ t('admin.errorPassthrough.columns.platforms') }}
+              </th>
+              <th class="px-3 py-2 text-left text-xs font-medium uppercase text-gray-500 dark:text-gray-400">
+                {{ t('admin.errorPassthrough.columns.behavior') }}
+              </th>
+              <th class="px-3 py-2 text-left text-xs font-medium uppercase text-gray-500 dark:text-gray-400">
+                {{ t('admin.errorPassthrough.columns.status') }}
+              </th>
+              <th class="px-3 py-2 text-left text-xs font-medium uppercase text-gray-500 dark:text-gray-400">
+                {{ t('admin.errorPassthrough.columns.actions') }}
+              </th>
+            </tr>
+          </thead>
+          <tbody class="divide-y divide-gray-200 bg-white dark:divide-dark-700 dark:bg-dark-800">
+            <tr v-for="rule in rules" :key="rule.id" class="hover:bg-gray-50 dark:hover:bg-dark-700">
+              <td class="whitespace-nowrap px-3 py-2">
+                <span class="inline-flex h-5 w-5 items-center justify-center rounded bg-gray-100 text-xs font-medium text-gray-700 dark:bg-dark-600 dark:text-gray-300">
+                  {{ rule.priority }}
+                </span>
+              </td>
+              <td class="px-3 py-2">
+                <div class="font-medium text-gray-900 dark:text-white text-sm">{{ rule.name }}</div>
+                <div v-if="rule.description" class="mt-0.5 text-xs text-gray-500 dark:text-gray-400 max-w-xs truncate">
+                  {{ rule.description }}
+                </div>
+              </td>
+              <td class="px-3 py-2">
+                <div class="flex flex-wrap gap-1 max-w-48">
+                  <span
+                    v-for="code in rule.error_codes.slice(0, 3)"
+                    :key="code"
+                    class="badge badge-danger text-xs"
+                  >
+                    {{ code }}
+                  </span>
+                  <span
+                    v-if="rule.error_codes.length > 3"
+                    class="text-xs text-gray-500"
+                  >
+                    +{{ rule.error_codes.length - 3 }}
+                  </span>
+                  <span
+                    v-for="keyword in rule.keywords.slice(0, 1)"
+                    :key="keyword"
+                    class="badge badge-gray text-xs"
+                  >
+                    "{{ keyword.length > 10 ? keyword.substring(0, 10) + '...' : keyword }}"
+                  </span>
+                  <span
+                    v-if="rule.keywords.length > 1"
+                    class="text-xs text-gray-500"
+                  >
+                    +{{ rule.keywords.length - 1 }}
+                  </span>
+                </div>
+                <div class="mt-0.5 text-xs text-gray-500 dark:text-gray-400">
+                  {{ t('admin.errorPassthrough.matchMode.' + rule.match_mode) }}
+                </div>
+              </td>
+              <td class="px-3 py-2">
+                <div v-if="rule.platforms.length === 0" class="text-xs text-gray-500 dark:text-gray-400">
+                  {{ t('admin.errorPassthrough.allPlatforms') }}
+                </div>
+                <div v-else class="flex flex-wrap gap-1">
+                  <span
+                    v-for="platform in rule.platforms.slice(0, 2)"
+                    :key="platform"
+                    class="badge badge-primary text-xs"
+                  >
+                    {{ platform }}
+                  </span>
+                  <span v-if="rule.platforms.length > 2" class="text-xs text-gray-500">
+                    +{{ rule.platforms.length - 2 }}
+                  </span>
+                </div>
+              </td>
+              <td class="px-3 py-2">
+                <div class="text-xs space-y-0.5">
+                  <div class="flex items-center gap-1">
+                    <Icon
+                      :name="rule.passthrough_code ? 'checkCircle' : 'xCircle'"
+                      size="xs"
+                      :class="rule.passthrough_code ? 'text-green-500' : 'text-gray-400'"
+                    />
+                    <span class="text-gray-600 dark:text-gray-400">
+                      {{ t('admin.errorPassthrough.code') }}:
+                      {{ rule.passthrough_code ? t('admin.errorPassthrough.passthrough') : (rule.response_code || '-') }}
+                    </span>
+                  </div>
+                  <div class="flex items-center gap-1">
+                    <Icon
+                      :name="rule.passthrough_body ? 'checkCircle' : 'xCircle'"
+                      size="xs"
+                      :class="rule.passthrough_body ? 'text-green-500' : 'text-gray-400'"
+                    />
+                    <span class="text-gray-600 dark:text-gray-400">
+                      {{ t('admin.errorPassthrough.body') }}:
+                      {{ rule.passthrough_body ? t('admin.errorPassthrough.passthrough') : t('admin.errorPassthrough.custom') }}
+                    </span>
+                  </div>
+                </div>
+              </td>
+              <td class="px-3 py-2">
+                <button
+                  @click="toggleEnabled(rule)"
+                  :class="[
+                    'relative inline-flex h-4 w-7 flex-shrink-0 cursor-pointer rounded-full border-2 border-transparent transition-colors duration-200 ease-in-out focus:outline-none focus:ring-2 focus:ring-primary-500 focus:ring-offset-2',
+                    rule.enabled ? 'bg-primary-600' : 'bg-gray-200 dark:bg-dark-600'
+                  ]"
+                >
+                  <span
+                    :class="[
+                      'pointer-events-none inline-block h-3 w-3 transform rounded-full bg-white shadow ring-0 transition duration-200 ease-in-out',
+                      rule.enabled ? 'translate-x-3' : 'translate-x-0'
+                    ]"
+                  />
+                </button>
+              </td>
+              <td class="px-3 py-2">
+                <div class="flex items-center gap-1">
+                  <button
+                    @click="handleEdit(rule)"
+                    class="p-1 text-gray-500 hover:text-primary-600 dark:hover:text-primary-400"
+                    :title="t('common.edit')"
+                  >
+                    <Icon name="edit" size="sm" />
+                  </button>
+                  <button
+                    @click="handleDelete(rule)"
+                    class="p-1 text-gray-500 hover:text-red-600 dark:hover:text-red-400"
+                    :title="t('common.delete')"
+                  >
+                    <Icon name="trash" size="sm" />
+                  </button>
+                </div>
+              </td>
+            </tr>
+          </tbody>
+        </table>
+      </div>
+    </div>
+
+    <template #footer>
+      <div class="flex justify-end">
+        <button @click="$emit('close')" class="btn btn-secondary">
+          {{ t('common.close') }}
+        </button>
+      </div>
+    </template>
+
+    <!-- Create/Edit Modal -->
+    <BaseDialog
+      :show="showCreateModal || showEditModal"
+      :title="showEditModal ? t('admin.errorPassthrough.editRule') : t('admin.errorPassthrough.createRule')"
+      width="wide"
+      @close="closeFormModal"
+    >
+      <form @submit.prevent="handleSubmit" class="space-y-4">
+        <!-- Basic Info -->
+        <div class="grid grid-cols-2 gap-4">
+          <div>
+            <label class="input-label">{{ t('admin.errorPassthrough.form.name') }}</label>
+            <input
+              v-model="form.name"
+              type="text"
+              required
+              class="input"
+              :placeholder="t('admin.errorPassthrough.form.namePlaceholder')"
+            />
+          </div>
+          <div>
+            <label class="input-label">{{ t('admin.errorPassthrough.form.priority') }}</label>
+            <input
+              v-model.number="form.priority"
+              type="number"
+              min="0"
+              class="input"
+            />
+            <p class="input-hint">{{ t('admin.errorPassthrough.form.priorityHint') }}</p>
+          </div>
+        </div>
+
+        <div>
+          <label class="input-label">{{ t('admin.errorPassthrough.form.description') }}</label>
+          <input
+            v-model="form.description"
+            type="text"
+            class="input"
+            :placeholder="t('admin.errorPassthrough.form.descriptionPlaceholder')"
+          />
+        </div>
+
+        <!-- Match Conditions -->
+        <div class="rounded-lg border border-gray-200 p-3 dark:border-dark-600">
+          <h4 class="mb-2 text-sm font-medium text-gray-900 dark:text-white">
+            {{ t('admin.errorPassthrough.form.matchConditions') }}
+          </h4>
+
+          <div class="grid grid-cols-2 gap-3">
+            <div>
+              <label class="input-label text-xs">{{ t('admin.errorPassthrough.form.errorCodes') }}</label>
+              <input
+                v-model="errorCodesInput"
+                type="text"
+                class="input text-sm"
+                :placeholder="t('admin.errorPassthrough.form.errorCodesPlaceholder')"
+              />
+              <p class="input-hint text-xs">{{ t('admin.errorPassthrough.form.errorCodesHint') }}</p>
+            </div>
+            <div>
+              <label class="input-label text-xs">{{ t('admin.errorPassthrough.form.keywords') }}</label>
+              <textarea
+                v-model="keywordsInput"
+                rows="2"
+                class="input font-mono text-xs"
+                :placeholder="t('admin.errorPassthrough.form.keywordsPlaceholder')"
+              />
+              <p class="input-hint text-xs">{{ t('admin.errorPassthrough.form.keywordsHint') }}</p>
+            </div>
+          </div>
+
+          <div class="mt-3">
+            <label class="input-label text-xs">{{ t('admin.errorPassthrough.form.matchMode') }}</label>
+            <div class="mt-1 space-y-2">
+              <label
+                v-for="option in matchModeOptions"
+                :key="option.value"
+                class="flex items-start gap-2 cursor-pointer"
+              >
+                <input
+                  type="radio"
+                  :value="option.value"
+                  v-model="form.match_mode"
+                  class="mt-0.5 h-3.5 w-3.5 border-gray-300 text-primary-600 focus:ring-primary-500"
+                />
+                <div class="flex-1">
+                  <span class="text-xs font-medium text-gray-700 dark:text-gray-300">{{ option.label }}</span>
+                  <p class="text-xs text-gray-500 dark:text-gray-400">{{ option.description }}</p>
+                </div>
+              </label>
+            </div>
+          </div>
+
+          <div class="mt-3">
+            <label class="input-label text-xs">{{ t('admin.errorPassthrough.form.platforms') }}</label>
+            <div class="flex flex-wrap gap-3">
+              <label
+                v-for="platform in platformOptions"
+                :key="platform.value"
+                class="inline-flex items-center gap-1.5"
+              >
+                <input
+                  type="checkbox"
+                  :value="platform.value"
+                  v-model="form.platforms"
+                  class="h-3.5 w-3.5 rounded border-gray-300 text-primary-600 focus:ring-primary-500"
+                />
+                <span class="text-xs text-gray-700 dark:text-gray-300">{{ platform.label }}</span>
+              </label>
+            </div>
+            <p class="input-hint text-xs mt-1">{{ t('admin.errorPassthrough.form.platformsHint') }}</p>
+          </div>
+        </div>
+
+        <!-- Response Behavior -->
+        <div class="rounded-lg border border-gray-200 p-3 dark:border-dark-600">
+          <h4 class="mb-2 text-sm font-medium text-gray-900 dark:text-white">
+            {{ t('admin.errorPassthrough.form.responseBehavior') }}
+          </h4>
+
+          <div class="grid grid-cols-2 gap-3">
+            <div>
+              <label class="flex items-center gap-1.5">
+                <input
+                  type="checkbox"
+                  v-model="form.passthrough_code"
+                  class="h-3.5 w-3.5 rounded border-gray-300 text-primary-600 focus:ring-primary-500"
+                />
+                <span class="text-xs font-medium text-gray-700 dark:text-gray-300">
+                  {{ t('admin.errorPassthrough.form.passthroughCode') }}
+                </span>
+              </label>
+              <div v-if="!form.passthrough_code" class="mt-2">
+                <label class="input-label text-xs">{{ t('admin.errorPassthrough.form.responseCode') }}</label>
+                <input
+                  v-model.number="form.response_code"
+                  type="number"
+                  min="100"
+                  max="599"
+                  class="input text-sm"
+                  placeholder="422"
+                />
+              </div>
+            </div>
+            <div>
+              <label class="flex items-center gap-1.5">
+                <input
+                  type="checkbox"
+                  v-model="form.passthrough_body"
+                  class="h-3.5 w-3.5 rounded border-gray-300 text-primary-600 focus:ring-primary-500"
+                />
+                <span class="text-xs font-medium text-gray-700 dark:text-gray-300">
+                  {{ t('admin.errorPassthrough.form.passthroughBody') }}
+                </span>
+              </label>
+              <div v-if="!form.passthrough_body" class="mt-2">
+                <label class="input-label text-xs">{{ t('admin.errorPassthrough.form.customMessage') }}</label>
+                <input
+                  v-model="form.custom_message"
+                  type="text"
+                  class="input text-sm"
+                  :placeholder="t('admin.errorPassthrough.form.customMessagePlaceholder')"
+                />
+              </div>
+            </div>
+          </div>
+        </div>
+
+        <!-- Enabled -->
+        <div class="flex items-center gap-1.5">
+          <input
+            type="checkbox"
+            v-model="form.enabled"
+            class="h-3.5 w-3.5 rounded border-gray-300 text-primary-600 focus:ring-primary-500"
+          />
+          <span class="text-xs font-medium text-gray-700 dark:text-gray-300">
+            {{ t('admin.errorPassthrough.form.enabled') }}
+          </span>
+        </div>
+      </form>
+
+      <template #footer>
+        <div class="flex justify-end gap-3">
+          <button @click="closeFormModal" type="button" class="btn btn-secondary">
+            {{ t('common.cancel') }}
+          </button>
+          <button @click="handleSubmit" :disabled="submitting" class="btn btn-primary">
+            <Icon v-if="submitting" name="refresh" size="sm" class="mr-1 animate-spin" />
+            {{ showEditModal ? t('common.update') : t('common.create') }}
+          </button>
+        </div>
+      </template>
+    </BaseDialog>
+
+    <!-- Delete Confirmation -->
+    <ConfirmDialog
+      :show="showDeleteDialog"
+      :title="t('admin.errorPassthrough.deleteRule')"
+      :message="t('admin.errorPassthrough.deleteConfirm', { name: deletingRule?.name })"
+      :confirm-text="t('common.delete')"
+      :cancel-text="t('common.cancel')"
+      :danger="true"
+      @confirm="confirmDelete"
+      @cancel="showDeleteDialog = false"
+    />
+  </BaseDialog>
+</template>
+
+<script setup lang="ts">
+import { ref, reactive, computed, watch } from 'vue'
+import { useI18n } from 'vue-i18n'
+import { useAppStore } from '@/stores/app'
+import { adminAPI } from '@/api/admin'
+import type { ErrorPassthroughRule } from '@/api/admin/errorPassthrough'
+import BaseDialog from '@/components/common/BaseDialog.vue'
+import ConfirmDialog from '@/components/common/ConfirmDialog.vue'
+import Icon from '@/components/icons/Icon.vue'
+
+const props = defineProps<{
+  show: boolean
+}>()
+
+const emit = defineEmits<{
+  close: []
+}>()
+
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+void emit // suppress unused warning - emit is used via $emit in template
+
+const { t } = useI18n()
+const appStore = useAppStore()
+
+const rules = ref<ErrorPassthroughRule[]>([])
+const loading = ref(false)
+const submitting = ref(false)
+const showCreateModal = ref(false)
+const showEditModal = ref(false)
+const showDeleteDialog = ref(false)
+const editingRule = ref<ErrorPassthroughRule | null>(null)
+const deletingRule = ref<ErrorPassthroughRule | null>(null)
+
+// Form inputs for arrays
+const errorCodesInput = ref('')
+const keywordsInput = ref('')
+
+const form = reactive({
+  name: '',
+  enabled: true,
+  priority: 0,
+  match_mode: 'any' as 'any' | 'all',
+  platforms: [] as string[],
+  passthrough_code: true,
+  response_code: null as number | null,
+  passthrough_body: true,
+  custom_message: null as string | null,
+  description: null as string | null
+})
+
+const matchModeOptions = computed(() => [
+  { value: 'any', label: t('admin.errorPassthrough.matchMode.any'), description: t('admin.errorPassthrough.matchMode.anyHint') },
+  { value: 'all', label: t('admin.errorPassthrough.matchMode.all'), description: t('admin.errorPassthrough.matchMode.allHint') }
+])
+
+const platformOptions = [
+  { value: 'anthropic', label: 'Anthropic' },
+  { value: 'openai', label: 'OpenAI' },
+  { value: 'gemini', label: 'Gemini' },
+  { value: 'antigravity', label: 'Antigravity' }
+]
+
+// Load rules when dialog opens
+watch(() => props.show, (newVal) => {
+  if (newVal) {
+    loadRules()
+  }
+})
+
+const loadRules = async () => {
+  loading.value = true
+  try {
+    rules.value = await adminAPI.errorPassthrough.list()
+  } catch (error) {
+    appStore.showError(t('admin.errorPassthrough.failedToLoad'))
+    console.error('Error loading rules:', error)
+  } finally {
+    loading.value = false
+  }
+}
+
+const resetForm = () => {
+  form.name = ''
+  form.enabled = true
+  form.priority = 0
+  form.match_mode = 'any'
+  form.platforms = []
+  form.passthrough_code = true
+  form.response_code = null
+  form.passthrough_body = true
+  form.custom_message = null
+  form.description = null
+  errorCodesInput.value = ''
+  keywordsInput.value = ''
+}
+
+const closeFormModal = () => {
+  showCreateModal.value = false
+  showEditModal.value = false
+  editingRule.value = null
+  resetForm()
+}
+
+const handleEdit = (rule: ErrorPassthroughRule) => {
+  editingRule.value = rule
+  form.name = rule.name
+  form.enabled = rule.enabled
+  form.priority = rule.priority
+  form.match_mode = rule.match_mode
+  form.platforms = [...rule.platforms]
+  form.passthrough_code = rule.passthrough_code
+  form.response_code = rule.response_code
+  form.passthrough_body = rule.passthrough_body
+  form.custom_message = rule.custom_message
+  form.description = rule.description
+  errorCodesInput.value = rule.error_codes.join(', ')
+  keywordsInput.value = rule.keywords.join('\n')
+  showEditModal.value = true
+}
+
+const handleDelete = (rule: ErrorPassthroughRule) => {
+  deletingRule.value = rule
+  showDeleteDialog.value = true
+}
+
+const parseErrorCodes = (): number[] => {
+  if (!errorCodesInput.value.trim()) return []
+  return errorCodesInput.value
+    .split(/[,\s]+/)
+    .map(s => parseInt(s.trim(), 10))
+    .filter(n => !isNaN(n) && n > 0)
+}
+
+const parseKeywords = (): string[] => {
+  if (!keywordsInput.value.trim()) return []
+  return keywordsInput.value
+    .split('\n')
+    .map(s => s.trim())
+    .filter(s => s.length > 0)
+}
+
+const handleSubmit = async () => {
+  if (!form.name.trim()) {
+    appStore.showError(t('admin.errorPassthrough.nameRequired'))
+    return
+  }
+
+  const errorCodes = parseErrorCodes()
+  const keywords = parseKeywords()
+
+  if (errorCodes.length === 0 && keywords.length === 0) {
+    appStore.showError(t('admin.errorPassthrough.conditionsRequired'))
+    return
+  }
+
+  submitting.value = true
+  try {
+    const data = {
+      name: form.name.trim(),
+      enabled: form.enabled,
+      priority: form.priority,
+      error_codes: errorCodes,
+      keywords: keywords,
+      match_mode: form.match_mode,
+      platforms: form.platforms,
+      passthrough_code: form.passthrough_code,
+      response_code: form.passthrough_code ? null : form.response_code,
+      passthrough_body: form.passthrough_body,
+      custom_message: form.passthrough_body ? null : form.custom_message,
+      description: form.description?.trim() || null
+    }
+
+    if (showEditModal.value && editingRule.value) {
+      await adminAPI.errorPassthrough.update(editingRule.value.id, data)
+      appStore.showSuccess(t('admin.errorPassthrough.ruleUpdated'))
+    } else {
+      await adminAPI.errorPassthrough.create(data)
+      appStore.showSuccess(t('admin.errorPassthrough.ruleCreated'))
+    }
+
+    closeFormModal()
+    loadRules()
+  } catch (error: any) {
+    appStore.showError(error.response?.data?.detail || t('admin.errorPassthrough.failedToSave'))
+    console.error('Error saving rule:', error)
+  } finally {
+    submitting.value = false
+  }
+}
+
+const toggleEnabled = async (rule: ErrorPassthroughRule) => {
+  try {
+    await adminAPI.errorPassthrough.toggleEnabled(rule.id, !rule.enabled)
+    rule.enabled = !rule.enabled
+  } catch (error: any) {
+    appStore.showError(error.response?.data?.detail || t('admin.errorPassthrough.failedToToggle'))
+    console.error('Error toggling rule:', error)
+  }
+}
+
+const confirmDelete = async () => {
+  if (!deletingRule.value) return
+
+  try {
+    await adminAPI.errorPassthrough.delete(deletingRule.value.id)
+    appStore.showSuccess(t('admin.errorPassthrough.ruleDeleted'))
+    showDeleteDialog.value = false
+    deletingRule.value = null
+    loadRules()
+  } catch (error: any) {
+    appStore.showError(error.response?.data?.detail || t('admin.errorPassthrough.failedToDelete'))
+    console.error('Error deleting rule:', error)
+  }
+}
+</script>