fix: task runs record the lane Celery really routes them to, and no healthy long job is swept as stalled (#4432)

celery_signals._queue_for was a hand-kept copy of task_routes and had
drifted:

- backup, admin and library_audit jobs, and backfill_phash, run on
  maintenance_long but were recorded as `maintenance`;
- translation and gpu_queue jobs were recorded as `default`, where the
  5-minute stall sweep failed healthy 35-minute translation runs.

It now asks the router, cached per task name.

A new guard test checks every registered task's hard time limit against
the stall threshold the sweep would use for it. It also caught these
sweeps, which failed healthy runs mid-flight and are fixed here:

- ml's scheduled sweeps (35 min, previously swept at 25);
- train_heads and apply_head_tags (65 min);
- import_media_file (6 min, previously swept at 5);
- the long lane, which now has its own 45-minute threshold.

UI changes:

- the admin job poller follows a job by celery_task_id, via a new filter
  on /runs, instead of by lane;
- the archive re-extract and missing-file repair cards show the long
  lane's backlog, where their jobs actually wait;
- the queue table lists maintenance_long.

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

backend/app/tasks/maintenance.py

@@ -137,7 +137,13 @@ IMPORT_BATCH_KEEP_DAYS = 30
 #   (the import queue itself stays at the 5-min default for single
 #   files); time_limit=2100.
 QUEUE_STUCK_THRESHOLD_MINUTES: dict[str, int] = {
-    "ml": 25,
+    # ml: the scheduled auto-apply sweeps and refresh_character_prototypes run
+    # to a 35-min hard limit (2100s); 25 swept them mid-run (#4432). The two
+    # 65-min jobs have their own entries below.
+    "ml": 40,
+    # import: import_media_file's hard limit is 6 min (360s), one past the
+    # 5-min default this queue fell to (#4432).
+    "import": 10,
     # download_source legitimately walks 5-25 min (Patreon/gallery-dl
     # deep creators); its hard time_limit is DOWNLOAD_HARD_TIME_LIMIT
     # (1500s = 25m). The 5-min default flagged healthy in-flight walks as
@@ -154,6 +160,12 @@ QUEUE_STUCK_THRESHOLD_MINUTES: dict[str, int] = {
     # overrides below cover the outliers (backups, library audit).
     "maintenance": 75,
     "scan": 75,
+    # The long lane (#4432). Until TaskRun.queue asked the router, nothing was
+    # recorded here: these runs read as `maintenance` (75) or, for
+    # translation, `default` (5 — which failed healthy 35-min runs). The
+    # longest task without its own entry below is the admin family at a
+    # 40-min hard limit; 45 = 40 + 5.
+    "maintenance_long": 45,
 }
 TASK_STUCK_THRESHOLD_MINUTES: dict[str, int] = {
     "backend.app.tasks.import_file.import_archive_file": 40,
@@ -179,6 +191,10 @@ TASK_STUCK_THRESHOLD_MINUTES: dict[str, int] = {
     # external-fetch entry above — without an override a healthy in-flight walk
     # is swept 'RecoverySweep' at the bare 5-min default. 30 = 25 + 5.
     "backend.app.tasks.admin.reclaim_orphaned_attachments_task": 30,
+    # Head training and the manual head apply run to 65 min (3900s) — past the
+    # ml queue's threshold (#4432). 70 = 65 + 5.
+    "backend.app.tasks.ml.train_heads": 70,
+    "backend.app.tasks.ml.apply_head_tags": 70,
 }