(ui) Add dashboard-linked run and snapshot lists

Add staff-only list pages for backup runs and snapshots with practical
filters, then wire the dashboard summary cards and latest-runs panel to
those overviews.

This gives the dashboard real drill-down paths for run and snapshot counts
instead of leaving the data only partially visible on the first screen.

Refs #23

src/pobsync_server/urls.py

@@ -34,6 +34,7 @@ urlpatterns = [
         name="cleanup_host_incomplete_snapshots",
     ),
     path("hosts/<str:host>/schedule/", views.edit_host_schedule, name="edit_host_schedule"),
+    path("runs/", views.runs_list, name="runs_list"),
     path("runs/<int:run_id>/", views.run_detail, name="run_detail"),
     path("runs/<int:run_id>/rsync-log/", views.run_rsync_log, name="run_rsync_log"),
     path("runs/<int:run_id>/cancel/", views.cancel_run, name="cancel_run"),
@@ -43,6 +44,7 @@ urlpatterns = [
         views.resolve_host_incomplete_reviews,
         name="resolve_host_incomplete_reviews",
     ),
+    path("snapshots/", views.snapshots_list, name="snapshots_list"),
     path("snapshots/<int:snapshot_id>/", views.snapshot_detail, name="snapshot_detail"),
     path("api/", api.api_index),
     path("api/status/", api.status),