修复报销附件上传与中文文件名（07-28-travel-reimbursement-guide）

server/tests/unit/services/purchaseAttachmentPolicy.test.js

@@ -542,4 +542,13 @@ describe("purchase attachment storage and response helpers", () => {
     expect(header).not.toContain("\\quote");
     expect(header).toContain("filename*=UTF-8''");
   });
+
+  it("supports safe inline Content-Disposition without changing the default", () => {
+    const header = buildAttachmentContentDisposition("铁路电子客票.pdf", { disposition: "inline" });
+
+    expect(header).toBe(
+      "inline; filename=\"attachment.pdf\"; filename*=UTF-8''%E9%93%81%E8%B7%AF%E7%94%B5%E5%AD%90%E5%AE%A2%E7%A5%A8.pdf",
+    );
+    expect(() => buildAttachmentContentDisposition("file.pdf", { disposition: "preview" })).toThrow(TypeError);
+  });
 });