Global thread watcher

[Kamuso]

Tag watcher in v7. Pings you when a thread is created on a board you're watching. Could use the selectedBoards local storage as the watched list.
Any opinions on the feature, or thoughts on how to detect thread creation?

[bakape]

thread descriptor:

{
  id: u64,
  tags: Vec<String>,
  post_count: u32,
  subject: String,
}

• On thread creation, send thread descriptor to all clients globally
• Cache current thread descriptors
  • Load on server start
  • Send to client on connection
• Send new post count on post open
• Send new tags on tag edit