Add configurable notification TTL (#24829)

* add configurable ttl for active alert notifications

Notifications sent while an alert was active always used a TTL of 0, so the push service dropped them if the device wasn't reachable at that moment and users only received the notification sent when the alert ended. A new `ttl` notifications option, settable globally or per camera, lets the push service retry these notifications for that many seconds. It defaults to 0, and the settings UI warns that a non-zero value can deliver stale notifications.

* make notification ttl a global advanced setting

- Read `ttl` from the global notifications config and hide it on the camera form
- Show it under Advanced Settings on the Notifications page
- Remove extra padding that misaligned the Notifications cards with the rest of the form
- Shorten the ttl warning

* tweaks

* use enum instead of raw seconds value

frigate/comms/webpush.py

@@ -22,6 +22,7 @@ from frigate.comms.base_communicator import Communicator
 from frigate.comms.config_updater import ConfigSubscriber
 from frigate.config import FrigateConfig
 from frigate.config.auth import AuthConfig
+from frigate.config.camera.notification import NOTIFICATION_TTL_SECONDS
 from frigate.config.camera.updater import (
     CameraConfigUpdateEnum,
     CameraConfigUpdateSubscriber,
@@ -623,7 +624,7 @@ class WebPushClient(Communicator):
 
         # if event is ongoing open to live view otherwise open to recordings view
         direct_url = f"/review?id={reviewId}" if ended else f"/#{camera}"
-        ttl = 3600 if ended else 0
+        ttl = 3600 if ended else NOTIFICATION_TTL_SECONDS[self.config.notifications.ttl]
 
         logger.debug(f"Sending push notification for {camera}, review ID {reviewId}")