Duplicates, delete & storage, users page with J-ID avatars

Backend:
- Perceptual hashes (aHash/dHash/pHash/wHash via imagehash, no imgdd)
  stored on items, computed on upload/download and by the new
  compute_visual_hashes command
- Duplicates API: exact duplicates (multi-location items), visual matches
  for one item, union-find similarity groups with pagination
- Delete API with ownership/staff checks, per-item and per-copy deletion,
  watched-folder path validation; storage overview and temp cleanup;
  file list accepts j_ids batches
- Staged uploads are flagged visual_match with their library matches
  (threshold via VISUAL_MATCH_THRESHOLD)
- Staff users API: list with upload counts, set role and avatar by J-ID;
  User.avatar FK with signed avatar URLs
- Download threads close their DB connection and stale tasks are reaped,
  keeping behaviour Gunicorn-friendly

Frontend:
- /duplicates: exact duplicate groups with per-copy delete, visual
  similarity controls, search similar to a J-ID, paginated groups with
  selection, bulk delete and dismiss
- /delete: storage cards, delete by J-ID with preview grid, temp cleanup
- /users: staff directory with role selects and avatar J-ID inputs
- Nav + command palette entries; top-bar avatar; upload cards and the
  metadata modal show library visual matches

backend/apps/library/urls.py

@@ -1,6 +1,14 @@
 from django.urls import include, path
 from rest_framework.routers import DefaultRouter
 
+from .tools import (
+    ClearTempView,
+    DeleteFilesView,
+    ExactDuplicatesView,
+    StorageView,
+    VisualGroupsView,
+    VisualMatchesView,
+)
 from .uploads import TempUploadViewSet
 from .views import ClientDownloadView, DownloadTaskViewSet, MediaItemViewSet
 
@@ -12,4 +20,22 @@ router.register("online/downloads", DownloadTaskViewSet, basename="download")
 urlpatterns = [
     path("", include(router.urls)),
     path("online/file/", ClientDownloadView.as_view(), name="client_download"),
+    path(
+        "duplicates/md5/",
+        ExactDuplicatesView.as_view(),
+        name="duplicates_md5",
+    ),
+    path(
+        "duplicates/visual/",
+        VisualMatchesView.as_view(),
+        name="duplicates_visual",
+    ),
+    path(
+        "duplicates/visual_groups/",
+        VisualGroupsView.as_view(),
+        name="duplicates_groups",
+    ),
+    path("delete/", DeleteFilesView.as_view(), name="delete_files"),
+    path("temp/clear/", ClearTempView.as_view(), name="clear_temp"),
+    path("storage/", StorageView.as_view(), name="storage_info"),
 ]