fix(formula): 导出文件安全、清理回收、撤权校验与定义库可靠性（F01/F02/F05-F08）

- F01: _safe_unlink_export 不跟随符号链接、逐层校验父目录，导出失败路径与
  清理命令统一使用，只清理受控目录内本次创建的文件
- F02: 清理失败记录告警日志；清理命令回收 failed 任务残留文件
- F05: 定义保存事务内锁数据集行，配额原子检查；revision 冲突返回 409；
  保留最近 20 版历史；支持个人/团队共享；审计与变更同事务
- F06: 工作簿参数页毛利率改为只读快照；可编辑单元格解锁并加数值校验
- F07: 对账按指标分容差（人数 0、比率 0.0001、金额 0.01）；自定义列使用
  服务端 Decimal 表达式求值参考
- F08: 导出任务执行/下载阶段重校验账号有效性与角色
- 对话草稿会话恢复；载入定义后追问携带原定义（F04）；下载改浏览器直传
- 迁移 0006-0008；PostgreSQL 咨询锁语义修正（import_worker）

tests/test_operations.py

@@ -46,6 +46,23 @@ def test_worker_processes_queued_import_and_formula_export(workspace):
     assert job.status == "processing"
 
 
+def test_worker_reclaims_processing_formula_export_after_restart(workspace):
+    ds, _, _, *_ = workspace
+    job = FormulaExport.objects.create(
+        dataset=ds,
+        user=ds.created_by,
+        context={"custom_columns": []},
+        status="processing",
+    )
+    from unittest.mock import patch
+
+    with patch(
+        "finance.management.commands.import_worker.process_formula_export", return_value={"rows": 5}
+    ) as process:
+        call_command("import_worker", once=True)
+    process.assert_called_once_with(job.pk)
+
+
 def test_formula_export_status_download_and_access_controls(workspace, settings, tmp_path):
     ds, _, client, _, other_client = workspace
     url = f"/api/datasets/{ds.pk}"
@@ -58,7 +75,7 @@ def test_formula_export_status_download_and_access_controls(workspace, settings,
     job.status = "succeeded"
     job.expires_at = timezone.now() + timedelta(hours=1)
     target = tmp_path / "formula-exports" / str(ds.created_by_id) / f"{job.pk}.xlsx"
-    target.parent.mkdir(parents=True)
+    target.parent.mkdir(parents=True, exist_ok=True)
     target.write_bytes(b"xlsx")
     job.path = str(target)
     job.save()
@@ -85,6 +102,29 @@ def test_formula_export_status_download_and_access_controls(workspace, settings,
     assert client.get(status_url).status_code == 403
 
 
+def test_formula_export_rechecks_role_when_worker_runs_and_file_is_downloaded(workspace, settings, tmp_path):
+    from finance.exporting import process_formula_export
+
+    ds, member, client, _, _ = workspace
+    job = FormulaExport.objects.create(dataset=ds, user=ds.created_by, context={}, status="processing")
+    member.role = "viewer"
+    member.save(update_fields=["role"])
+    with pytest.raises(PermissionError, match="撤权"):
+        process_formula_export(job.pk)
+    job.refresh_from_db()
+    assert job.status == "failed"
+
+    job.status = "succeeded"
+    job.expires_at = timezone.now() + timedelta(hours=1)
+    target = tmp_path / "formula-exports" / str(ds.created_by_id) / f"{job.pk}.xlsx"
+    target.parent.mkdir(parents=True, exist_ok=True)
+    target.write_bytes(b"xlsx")
+    job.path = str(target)
+    job.save(update_fields=["status", "expires_at", "path"])
+    assert client.get(f"/api/datasets/{ds.pk}/formula-exports/{job.pk}").status_code == 403
+    assert client.get(f"/api/datasets/{ds.pk}/formula-exports/{job.pk}/download").status_code == 403
+
+
 def test_formula_export_create_validates_definition_and_records_job(workspace):
     ds, _, client, *_ = workspace
     url = f"/api/datasets/{ds.pk}/formula-exports"