fix: 审批附件落盘改到上传根目录，修复预览/下载 404（#44）

src/main/java/com/gxwebsoft/approval/service/ApprovalAttachmentService.java

@@ -116,8 +116,10 @@ public class ApprovalAttachmentService {
     File stored;
     String path;
     try {
+      // 直接落盘到上传根目录：记录路径须与 /api/file/{dir}/{name} 的物理解析一致，
+      // 任何子目录前缀都要同步出现在记录 path 与文件服务路由里（回归 #44）
       String base = config.getUploadPath();
-      String dir = (base.endsWith("/") ? base : base + "/") + "approval/";
+      String dir = base.endsWith("/") ? base : base + "/";
       stored = FileServerUtil.upload(file, dir, Boolean.TRUE.equals(config.getUploadUuidName()));
       path = stored.getAbsolutePath().replace("\\", "/").substring(dir.length() - 1);
     } catch (Exception e) {

src/test/java/com/gxwebsoft/approval/ApprovalAttachmentFileRoundTripIT.java

@@ -0,0 +1,135 @@
+package com.gxwebsoft.approval;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.gxwebsoft.support.ApprovalTestData;
+import com.gxwebsoft.support.TestAuthentication;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.MediaType;
+import org.springframework.mock.web.MockMultipartFile;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.MvcResult;
+
+import javax.sql.DataSource;
+import java.nio.charset.StandardCharsets;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.authentication;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.multipart;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+/**
+ * 附件「上传 → 文件端点取回」往返集成测试（回归 #44）。
+ *
+ * <p>附件上传成功后，H5 详情页按返回的 url 直接打开原文件；该 url 依赖
+ * sys_file_record.path 与落盘物理路径一致。路径错位时预览/下载全部 404，
+ * 且只有一次真实往返能发现。</p>
+ *
+ * <p>不加 {@code @Transactional}：下载端点经 {@code @DS("server")} 的
+ * FileRecordService 查文件记录，测试事务会把连接钉死在 master（该表在 core 库），
+ * 与生产无事务的调用形态不符；数据隔离由 {@link ApprovalTestData#cleanup()} 负责。</p>
+ */
+@SpringBootTest
+@AutoConfigureMockMvc
+@ActiveProfiles({"gxtyzx-test", "test"})
+class ApprovalAttachmentFileRoundTripIT {
+
+  private static final int TENANT = TestAuthentication.TENANT_ID;
+  private static final String SUBMIT = "approval:instance:submit";
+
+  @Autowired
+  private MockMvc mockMvc;
+  @Autowired
+  private ObjectMapper objectMapper;
+  @Autowired
+  private DataSource dataSource;
+
+  private ApprovalTestData data;
+  private ApprovalTestData.TestUser reporter;
+  private Integer organizationId;
+
+  @BeforeEach
+  void setUp() {
+    data = new ApprovalTestData(dataSource);
+    organizationId = data.createOrganization("测试部门" + data.uniqueSuffix(), 136);
+    reporter = data.createUser("报送人" + data.uniqueSuffix(), organizationId);
+  }
+
+  @AfterEach
+  void tearDown() {
+    data.cleanup();
+  }
+
+  @Test
+  void uploadedAttachmentIsFetchableThroughPreviewAndDownloadEndpoints() throws Exception {
+    long instanceId = createCompletionDraft("附件往返");
+    JsonNode attachment = uploadAttachment(instanceId);
+    String url = attachment.path("url").asText();
+    assertThat(url).contains("/file/");
+
+    // 前端拿到的 url 去掉 scheme/host 后必须能直接 GET 到原文件（浏览器 window.open 无登录态）
+    String fetchPath = "/api" + url.substring(url.indexOf("/file/"));
+    byte[] payload = pngBytes();
+
+    MvcResult preview = mockMvc.perform(get(fetchPath))
+      .andExpect(status().isOk())
+      .andReturn();
+    assertThat(preview.getResponse().getContentAsByteArray()).isEqualTo(payload);
+
+    // 下载端点走同一条物理路径解析，一并回归
+    String downloadPath = fetchPath.replace("/api/file/", "/api/file/download/");
+    MvcResult download = mockMvc.perform(get(downloadPath))
+      .andExpect(status().isOk())
+      .andReturn();
+    assertThat(download.getResponse().getContentAsByteArray()).isEqualTo(payload);
+  }
+
+  // ---------- helpers ----------
+
+  private long createCompletionDraft(String name) throws Exception {
+    String body = "{\"name\":\"" + name + "\",\"implementOrg\":\"实施单位\",\"fee\":\"1.00\","
+      + "\"serviceContent\":\"服务内容\"}";
+    String response = mockMvc.perform(authed(post("/api/approval/instance/completion"))
+        .contentType(MediaType.APPLICATION_JSON)
+        .content(body))
+      .andExpect(status().isOk())
+      .andExpect(jsonPath("$.code").value(0))
+      .andReturn().getResponse().getContentAsString(StandardCharsets.UTF_8);
+    long id = objectMapper.readTree(response).path("data").asLong();
+    data.trackInstance(id);
+    return id;
+  }
+
+  private JsonNode uploadAttachment(long instanceId) throws Exception {
+    MockMultipartFile file = new MockMultipartFile("file", "sign.png", "image/png", pngBytes());
+    String response = mockMvc.perform(multipart("/api/approval/attachment/upload")
+        .file(file)
+        .param("instanceId", String.valueOf(instanceId))
+        .param("category", "SIGNED")
+        .header("tenantId", TENANT)
+        .with(authentication(TestAuthentication.user(reporter.userId, reporter.username, organizationId, TENANT, SUBMIT))))
+      .andExpect(status().isOk())
+      .andExpect(jsonPath("$.code").value(0))
+      .andReturn().getResponse().getContentAsString(StandardCharsets.UTF_8);
+    return objectMapper.readTree(response).path("data");
+  }
+
+  private byte[] pngBytes() {
+    return new byte[]{(byte) 0x89, 'P', 'N', 'G', 0x0D, 0x0A, 0x1A, 0x0A};
+  }
+
+  private org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder authed(
+    org.springframework.test.web.servlet.request.MockHttpServletRequestBuilder builder) {
+    return builder.header("tenantId", TENANT)
+      .with(authentication(TestAuthentication.user(reporter.userId, reporter.username, organizationId, TENANT, SUBMIT)));
+  }
+}