Nickname autocomplete

As a user, I want to be able to easily reference another user.

When I long press on a Nickname, I addition to reactions, I want the following options presented:

+ "Mention" (in Group channels)

++ When new message area is empty or only contains whitespace, clear and pre-populate the text entry field, referencing the user, e.g. "Nickname[:][[:space:]]"

++ When the new message area contains non-whitespace:

+++ If the cursor has a non-whitespace character to the left, insert "[[:space:]]"

+++ Then, insert "Nickname[[:space:]]"

+ "Message"

++ Open a new or switch to existing Message window for "Nickname"

+ "Info", either/both

++ Show user info

++ Show an expanded view (similar to the Discord Nickname long press response)

When I tap on a recognised / Hyperlinked Nickname in a message, I want to be shown the same dialogue as above, and not sent to "matrix.to/#/@[Nickname]:matrix.org". This information could be incorporated (and cached) to be shown as part of the UserInfo.

When I am in the text entry area and tap on a User or Nickname or Hyperlinked Nickname within a message, then

+ If the text area is empty, or only contains whitespace, clear the text area and insert "Nickname[:][[:space:]]", otherwise

+ If previous character is not a space, insert a space (i.e. "[[:space:]]")

+++ Then, insert "Nickname[[:space:]]"