refactor: 前端全面替换 any 为 unknown 并统一错误处理，后端用量记录补写请求头/体

- 前端 API 层、stores、conversation 解析器、组件全面替换 any 为 unknown/具体类型
- 错误处理统一使用 parseApiError/getErrorStatus 替代 err.response?.data?.detail 模式
- 后端 handler/TaskService/UsageLifecycle/StreamTracker 链路传递 request_headers/request_body
- streaming/pending 状态更新时可补写客户端和提供商的请求头及请求体
- 新增 TaskService 和 UsageService 相关测试

frontend/src/features/providers/components/KeyAllowedModelsDialog.vue

@@ -191,7 +191,7 @@ import Button from '@/components/ui/button.vue'
 import Badge from '@/components/ui/badge.vue'
 import Checkbox from '@/components/ui/checkbox.vue'
 import { useToast } from '@/composables/useToast'
-import { parseUpstreamModelError } from '@/utils/errorParser'
+import { parseApiError, parseUpstreamModelError } from '@/utils/errorParser'
 import {
   importModelsFromUpstream,
   getProviderModels,
@@ -305,9 +305,8 @@ async function fetchUpstreamModels() {
       // 上游返回空列表但无错误
       hasQueried.value = true
     }
-  } catch (err: any) {
-    const rawError = err.response?.data?.detail || err.message || '获取上游模型失败'
-    errorMessage.value = parseUpstreamModelError(rawError)
+  } catch (err: unknown) {
+    errorMessage.value = parseUpstreamModelError(parseApiError(err, '获取上游模型失败'))
   } finally {
     loading.value = false
   }
@@ -378,8 +377,8 @@ async function handleImport() {
       const errorMsg = response.errors?.[0]?.error || '导入失败'
       showError(errorMsg, '导入失败')
     }
-  } catch (err: any) {
-    showError(err.response?.data?.detail || '导入失败', '错误')
+  } catch (err: unknown) {
+    showError(parseApiError(err, '导入失败'), '错误')
   } finally {
     importing.value = false
   }