Reaction notification does not navigate to the reacted message

Steps to reproduce

1. User A sends a message in a Talk conversation.
2. User B reacts to that message (👍, ❤️, 👀, etc.).
3. User A receives a push notification on the iOS app informing them about the reaction.
4. Tap the push notification.

Expected behaviour

The app should:

* Open the correct conversation.
* Automatically scroll to the message that received the reaction.
* Optionally highlight the reacted message for a short time to make it easy to identify.

This is especially important in active conversations where manually finding the message can be difficult.

Actual behaviour

The push notification is delivered correctly and tapping it opens the correct conversation.

However:

* The conversation is opened at the current/default position.
* The app does not scroll to the reacted message.
* The reacted message is not highlighted.
* There is no visual indication showing which message received the new reaction.

As a result, the user has to manually search through the conversation to find the reacted message.

This issue is reproducible every time.

## Additional feature request

It would also be useful to have an option to enable or disable notifications for message reactions independently from other notification types.

For example:

- ✅ Messages
- ✅ Mentions
- ✅ Replies
- ❌ Reactions

In busy conversations, reactions can generate a large number of notifications, while many users may not consider them important enough to receive push notifications.

⸻

Device information

Device: iPhone 17

iOS version: 26.5.1

Talk version (Mobile App): 24.0.2

Server information

Nextcloud version: 33.0.3

Talk version: 23.0.6

Custom Signaling server configured: Yes (standalone signaling server)

Custom TURN server configured: Yes

Custom STUN server configured: No (TURN only)

Server log (data/nextcloud.log)

No relevant server-side errors are logged when the issue occurs.

Start by tracing the iOS push-notification tap handling described in the issue through conversation navigation. Confirm that a reaction notification opens the conversation at the reacted message, provides the requested visual indication, and assess the separate notification-toggle request; no files or tests are named.

Written by the indexing model from the issue text.