feat(server): 报销单输出工号/邮箱并扩展申请人邮箱前缀匹配

- ExpenseClaimRead 新增 employee_no/employee_email 字段，ExpenseClaim 模型补对应只读属性
- expense_claim_access_policy 在姓名匹配未果时，按 candidate@% 邮箱前缀匹配 Employee.email，命中唯一记录即返回
- test_backend_pagination/test_expense_claim_service 补充工号/邮箱字段断言与邮箱前缀匹配用例
- 更新公司通信费报销规则表

server/tests/test_backend_pagination.py

@@ -105,6 +105,8 @@ def test_expense_claims_support_page_envelope_and_keep_legacy_list() -> None:
     assert payload["total_pages"] == 2
     assert payload["has_next"] is True
     assert payload["has_previous"] is False
+    assert payload["items"][0]["employee_no"] == "E-PAGE"
+    assert payload["items"][0]["employee_email"] == "page-user@example.com"
 
 
 def test_employee_directory_supports_backend_pagination() -> None: