## Issue
One of the bottlenecks of livestream page.
The component probably needs a re-design:
- Don't perpetually mount -- only mount when activated by the user through "@". This would avoid the heavy processing entirely.
- Better way of resolving uris (too many arrays, too many loops).
- Tom also mentioned that we should not be resolving every commenter as we see encounter them in a livestream. This is currently the case because the component is always mounted.
## Changes
Until the re-design occurs, attempt to cache the heavy processing. Also, trimmed down the amount of loops.
As long as the input parameters are the same, the selector will return the cached value so that we don't construct the list twice, which involves blocklist filtering.
* Add Channel Mention selection ability
* Fix mentioned user name being smaller than other text
* Improve logic for locating a mention
* Fix mentioning with enter on livestream
* Fix breaking for invalid URI query
* Handle punctuation after mention
* Fix name display and appeareance
* Use canonical url
* Fix missing search
