[Feature request] sound notification upon new Newsfeed entry

Hello, this is certainly low importance thing, i apologize if it should not be posted there.

Some web pages are producing sound notifications, example when page has an online chat and support staff just sent you a message. Even if i switch to other tab, it can remind me there is something new.

So i was thinking it may be good if there is sound notification when there is new Newsfeed entry on ZeroHello page (especially one that mentions you). Sound of mention can differ from new post sound. I think it may increase interaction between users and make the discussion on Zeronet more used/beneficial/alive.

In Firefox if one want to mute the sounds for certain tab, one just click speaker icon on the tab.

May be good if user can change sound by a hack or in UI or possibly toggle sounds by an icon (default = sound off)

UPDATE: "desktop notifications" feature request here: https://github.com/HelloZeroNet/ZeroHello/issues/52

首先定位 ZeroHello Newsfeed 的入口点，以及如何检测新条目，尤其是提及。检查所请求的声音行为，区分提及声音和普通帖子声音，并研究可能的用户控制选项。完成内容应包括明确的通知策略，以及针对新条目和提及的已验证行为。

由索引模型根据 Issue 内容生成。