Miscellaneous fixes (#24820)

* keep base path in logout redirect

* store manual event sub labels as verified objects

Manual events created with a sub label were stored in the review item as "label: sub_label", so review previews and collapsed History cards showed a generic icon, the review label filter missed them, and the sub label never reached sub_labels for chips, notifications, or GenAI prompts. The object processor now publishes the label and sub label separately, and the review maintainer stores them as label-verified plus a sub_labels entry, the same as tracked objects.

* only expire snapshots for events that still have one

Snapshot expiry selected every event older than snapshot retention, including events whose snapshot was already deleted, so with snapshot retention shorter than alert/detection retention the same missing files were unlinked again every cleanup cycle until the event row expired. That was nearly free on local disk but caused constant metadata load on network shares. The expiry queries now filter on has_snapshot so each snapshot is deleted once.

frigate/events/cleanup.py

@@ -93,6 +93,7 @@ class EventCleanup(threading.Thread):
                     Event.start_time < expire_after,
                     Event.label == event.label,
                     Event.retain_indefinitely == False,
+                    Event.has_snapshot == True,
                 )
                 .namedtuples()
                 .iterator()
@@ -114,6 +115,7 @@ class EventCleanup(threading.Thread):
                 Event.start_time < expire_after,
                 Event.label == event.label,
                 Event.retain_indefinitely == False,
+                Event.has_snapshot == True,
             )
 
             events_to_update: list[str] = []
@@ -169,6 +171,7 @@ class EventCleanup(threading.Thread):
                         Event.start_time < expire_after,
                         Event.label == event.label,
                         Event.retain_indefinitely == False,
+                        Event.has_snapshot == True,
                     )
                     .namedtuples()
                     .iterator()