fix: the download boot hook imports a model-only module, keeping the membership roster off the fetch path (#4433)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LVjrnpQjRgHdvq95rASoiR

backend/app/tasks/maintenance.py

@@ -7,8 +7,7 @@ from datetime import UTC, datetime, timedelta
 from pathlib import Path
 
 from PIL import Image
-from sqlalchemy import Integer, and_, cast, delete, func, literal, or_, select, update
-from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy import Integer, and_, cast, delete, func, or_, select, update
 
 from ..celery_app import celery
 from ..models import (
@@ -732,48 +731,6 @@ def recover_stalled_download_events() -> int:
         return events_recovered
 
 
-DOWNLOAD_INTERRUPTED_MESSAGE = (
-    "interrupted by a worker restart — the next check picks it up where it left off"
-)
-
-
-def interrupt_orphaned_download_events(session, *, booted_at: datetime) -> int:
-    """Close the download events a restart orphaned, without blaming the source.
-
-    Called when the download lane comes up (#4433). Anything still
-    pending/running from before this boot belongs to the previous process:
-    a walk that outlived the 90s stop grace was SIGKILLed, and a queued or
-    serialize-deferred task is held unacked until Redis redelivers it about an
-    hour later. Left alone, the 30-min stall sweep would error each one and
-    bump `consecutive_failures`, backing the source off as if the platform had
-    failed.
-
-    Instead they end as `skipped` (terminal, not a failure) and the source is
-    not touched: `last_checked_at` keeps its old value, so the next tick finds
-    it due and the walk resumes from its checkpoint. A redelivered message
-    that arrives later finds no pending event and opens a fresh one.
-
-    An event promoted to running after the boot has `started_at` reset to its
-    real start (download_service), so it is never caught here. Does NOT commit.
-    """
-    now = datetime.now(UTC)
-    result = session.execute(
-        update(DownloadEvent)
-        .where(DownloadEvent.status.in_(["pending", "running"]))
-        .where(DownloadEvent.started_at < booted_at)
-        .values(
-            status="skipped",
-            finished_at=now,
-            error=DOWNLOAD_INTERRUPTED_MESSAGE,
-            metadata_=DownloadEvent.metadata_.op("||")(
-                literal({"error_type": "interrupted"}, JSONB)
-            ),
-        )
-        .returning(DownloadEvent.id)
-    )
-    return len(result.all())
-
-
 @celery.task(name="backend.app.tasks.maintenance.recover_stalled_backup_runs")
 def recover_stalled_backup_runs() -> int:
     """Flip BackupRun rows stuck in running/restoring past the hard limit