Separate tap actions for display name and avatar (match Element Android behavior)

#### What would you like to do?

Have Element X separate tap actions on usernames and avatars — just like Element Android does.

Tap the display name → insert a @mention in the composer.

Tap the avatar → open the user’s details.

#### Why would you like to do it?

This improves usability and consistency with Element Android.
It allows quick mentions during active conversations while still providing easy access to user profiles.

#### How would you like to achieve it?

Adjust the tap handling logic so the display name and avatar trigger different actions.

For example:
Keep the current “open user details” behavior for avatar taps.

Add the “@mention” action when tapping the display name.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

### Are you willing to provide a PR?

No