Miscellaneous fixes (#23610)

* Handle back seeking going to previous clip

* scope /recordings/unavailable query to the caller's allowed cameras

* listen for config updates in activity manager

* don't set search after awaited request

Intentionally do NOT setSearch() to mark the open event submitted. This runs after the awaited request, by which point the user may have closed the dialog; re-setting the parent's selected event would resurrect it and the force-open effect would reopen it (see #23599). The local "submitted" state covers the open card, and mutate() updates the events cache so the grid and any future open reflect the result.

* fix ruff

#23201 removed pathlib import but for some reason it's just now causing ruff to fail

---------

Co-authored-by: Nicolas Mowen <nickmowen213@gmail.com>

frigate/camera/activity_manager.py

@@ -13,6 +13,10 @@ from frigate.comms.event_metadata_updater import (
     EventMetadataTypeEnum,
 )
 from frigate.config import CameraConfig, FrigateConfig
+from frigate.config.camera.updater import (
+    CameraConfigUpdateEnum,
+    CameraConfigUpdateSubscriber,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -29,6 +33,11 @@ class CameraActivityManager:
         self.zone_all_object_counts: dict[str, Counter] = {}
         self.zone_active_object_counts: dict[str, Counter] = {}
         self.all_zone_labels: dict[str, set[str]] = {}
+        self.config_subscriber = CameraConfigUpdateSubscriber(
+            config,
+            config.cameras,
+            [CameraConfigUpdateEnum.zones, CameraConfigUpdateEnum.objects],
+        )
 
         for camera_config in config.cameras.values():
             if not camera_config.enabled_in_config:
@@ -56,7 +65,40 @@ class CameraActivityManager:
                 else camera_config.objects.track
             )
 
+    def __rebuild_zone_labels(self) -> None:
+        """Rebuild zone label tracking after a runtime zones/objects change."""
+        new_zone_labels: dict[str, set[str]] = {}
+
+        for camera_config in self.config.cameras.values():
+            if not camera_config.enabled_in_config or camera_config.name is None:
+                continue
+
+            for zone, zone_config in camera_config.zones.items():
+                new_zone_labels.setdefault(zone, set()).update(
+                    zone_config.objects
+                    if zone_config.objects
+                    else camera_config.objects.track
+                )
+
+        # drop counters for zones that no longer exist
+        for zone in list(self.zone_all_object_counts.keys()):
+            if zone not in new_zone_labels:
+                self.zone_all_object_counts.pop(zone, None)
+                self.zone_active_object_counts.pop(zone, None)
+
+        # ensure counters exist for new zones so the first count is published
+        for zone in new_zone_labels:
+            self.zone_all_object_counts.setdefault(zone, Counter())
+            self.zone_active_object_counts.setdefault(zone, Counter())
+
+        self.all_zone_labels = new_zone_labels
+
     def update_activity(self, new_activity: dict[str, dict[str, Any]]) -> None:
+        updated_topics = self.config_subscriber.check_for_updates()
+
+        if "zones" in updated_topics or "objects" in updated_topics:
+            self.__rebuild_zone_labels()
+
         all_objects: list[dict[str, Any]] = []
 
         for camera in new_activity.keys():
@@ -161,6 +203,9 @@ class CameraActivityManager:
             self.publish(f"{camera}/all", sum(list(all_objects.values())))
             self.publish(f"{camera}/all/active", sum(list(active_objects.values())))
 
+    def stop(self) -> None:
+        self.config_subscriber.stop()
+
 
 class AudioActivityManager:
     def __init__(