fix(http): 网络异常透传微信 errMsg，暴露真实失败原因（域名拦截/断网/超时）

src/http/client.ts

@@ -81,7 +81,9 @@ export async function request<T>(
       header: headers
     })
   } catch (e) {
-    throw new ApiError(e instanceof Error ? e.message : '网络异常')
+    // Taro 网络 API reject 的是 { errMsg } 形状对象而非 Error 实例，需兼容读取以便透出真实原因
+    const raw = e instanceof Error ? e.message : (e as { errMsg?: string })?.errMsg
+    throw new ApiError(raw || '网络异常')
   }
 
   if (res.statusCode !== 200) {

tests/unit/http/client.spec.ts

@@ -87,6 +87,22 @@ describe('client envelope 解析', () => {
     })
   })
 
+  it('Taro.request reject 的是 { errMsg } 形状对象时透传 errMsg（微信真实失败形态）', async () => {
+    mockRequest.mockRejectedValue({ errMsg: 'request:fail url not in domain list' })
+    await expect(request.get('/demo')).rejects.toMatchObject({
+      name: 'ApiError',
+      message: 'request:fail url not in domain list'
+    })
+  })
+
+  it('reject 无任何可读信息时兜底「网络异常」', async () => {
+    mockRequest.mockRejectedValue(undefined)
+    await expect(request.get('/demo')).rejects.toMatchObject({
+      name: 'ApiError',
+      message: '网络异常'
+    })
+  })
+
   it('需鉴权请求注入 Bearer token 头', async () => {
     mockRequest.mockResolvedValue(okBody(null))
     await request.get('/demo')