fix(worker): F08 执行/下载统一核验角色与账号状态，恢复卡死的 processing 任务

- worker 执行前重新核验账号 is_active 与 admin/analyst 角色：撤权/停用后排队任务
  直接失败，不发布敏感工作簿
- formula-exports 状态与下载接口补齐与创建接口一致的角色白名单，被降为 viewer
  的账号不能再查询/下载旧导出
- import_worker 对超过 15 分钟仍处于 processing 的任务重新认领（PostgreSQL 依赖
  咨询锁立即恢复），崩溃重启不再无限停留 processing；新近 processing 不被抢占
- 测试：撤权/停用执行、viewer 下载与状态 403、半成品/缺文件下载 409/410、
  超时任务恢复且无重复临时文件、新近 processing 不被重复认领

tests/test_worker_paths.py

@@ -1,7 +1,10 @@
+from datetime import timedelta
+from pathlib import Path
 from unittest.mock import patch
 
 import pytest
 from django.core.management import call_command
+from django.utils import timezone
 
 from finance.models import FormulaExport
 
@@ -26,3 +29,118 @@ def test_worker_processes_queued_import_and_reports_export_failure(workspace):
         call_command("import_worker", once=True)
     export.refresh_from_db()
     assert export.status == "processing"
+
+
+def _export_job(ds, **kwargs):
+    return FormulaExport.objects.create(
+        dataset=ds,
+        user=ds.created_by,
+        context={"start": "2026-08", "end": "2026-08", "comparison": "yoy", "group": "department"},
+        **kwargs,
+    )
+
+
+def test_worker_refuses_export_after_role_revocation(workspace):
+    from finance.exporting import process_formula_export
+
+    ds, member, *_ = workspace
+    job = _export_job(ds, status="processing")
+    member.role = "viewer"
+    member.save(update_fields=["role"])
+
+    with pytest.raises(PermissionError, match="角色"):
+        process_formula_export(job.pk)
+
+    job.refresh_from_db()
+    assert job.status == "failed"
+    assert not job.path
+    assert not list(Path(ds.file.storage.location).rglob(f"{job.pk}*"))
+
+
+def test_worker_refuses_export_after_account_deactivation(workspace):
+    from finance.exporting import process_formula_export
+
+    ds, _, _, _, _ = workspace
+    user = ds.created_by
+    user.is_active = False
+    user.save(update_fields=["is_active"])
+    job = _export_job(ds, status="processing")
+
+    with pytest.raises(PermissionError, match="停用"):
+        process_formula_export(job.pk)
+
+    job.refresh_from_db()
+    assert job.status == "failed"
+
+
+def test_status_and_download_deny_revoked_viewer(workspace, settings):
+    ds, member, client, *_ = workspace
+    job = _export_job(
+        ds,
+        status="succeeded",
+        finished_at=timezone.now(),
+        expires_at=timezone.now() + timedelta(hours=1),
+    )
+    target = Path(settings.MEDIA_ROOT) / "formula-exports" / str(job.user_id) / f"{job.pk}.xlsx"
+    target.parent.mkdir(parents=True)
+    target.write_bytes(b"PK workbook")
+    job.path = str(target)
+    job.save(update_fields=["path"])
+
+    assert client.get(f"/api/datasets/{ds.pk}/formula-exports/{job.pk}").status_code == 200
+    assert (
+        client.get(f"/api/datasets/{ds.pk}/formula-exports/{job.pk}/download").status_code == 200
+    )
+
+    member.role = "viewer"
+    member.save(update_fields=["role"])
+    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_half_finished_export_cannot_be_downloaded(workspace, settings):
+    ds, _, client, *_ = workspace
+    for status, code in (("processing", 409), ("failed", 409), ("queued", 409)):
+        job = _export_job(ds, status=status)
+        assert (
+            client.get(f"/api/datasets/{ds.pk}/formula-exports/{job.pk}/download").status_code
+            == code
+        ), status
+    succeeded = _export_job(
+        ds,
+        status="succeeded",
+        path=str(Path(settings.MEDIA_ROOT) / "nowhere.xlsx"),
+        finished_at=timezone.now(),
+        expires_at=timezone.now() + timedelta(hours=1),
+    )
+    assert (
+        client.get(f"/api/datasets/{ds.pk}/formula-exports/{succeeded.pk}/download").status_code
+        == 410
+    )
+
+
+def test_stale_processing_export_is_reclaimed_after_timeout(workspace):
+    ds, *_ = workspace
+    job = _export_job(ds, status="processing")
+    FormulaExport.objects.filter(pk=job.pk).update(
+        created_at=timezone.now() - timedelta(minutes=20)
+    )
+
+    call_command("import_worker", once=True)
+
+    job.refresh_from_db()
+    assert job.status == "succeeded"
+    assert Path(job.path).read_bytes()[:2] == b"PK"
+    assert not list(Path(job.path).parent.glob(f"{job.pk}.*.tmp"))
+
+
+def test_recent_processing_export_is_not_reclaimed(workspace):
+    ds, *_ = workspace
+    job = _export_job(ds, status="processing")
+
+    call_command("import_worker", once=True)
+
+    job.refresh_from_db()
+    assert job.status == "processing"