Use a single [userId, roomId] property for the chat page.
This gets read of the intermediate state where the userId property has
been updated but the roomId one not yet, which led to the page unloading
and reloading itself until both were properly set.
Side-effect: when starting Mirage after this commit for the first time,
the last saved page will not load and user must click a room or
other page manually.
The chat page is complex and slow to create, which creates a visible lag
when user switches room.
Instead of throwing the pre-switch one away and
making a new one from scratch, keep the same page and update its user &
room ID for a big improvement in responsiveness. The rest is automatic
thanks to QML property bindings.
Send a pseudo-reply consisting of two messages: a `m.text` which is just
a reply with an empty body, then the file event itself.
This is a workaround to the restriction imposed by the Matrix API,
which prevents us from simply attaching a reply to a media event:
https://matrix.org/docs/spec/client_server/latest#rich-replies
When auto-expanding a pane and showing it as an overlay because of
narrow window, make the chat keep the width it had before.
This makes the transition less jarring, reduces the amount of text seen
through a transparent pane, and fix making one pane overlay expanding
the other.
If the room pane is below the default width (by user resizing or because
of narrow window), go to the room settings or a member profile will
automatically expand it as needed.
The pane goes back to its previous size once the settings/profile is
left.
If the window is narrow enough that expanding the pane normally would
reduce the timeline's width past its minimum, the pane is shown as an
overlay instead.
Use native ListModel which require a lot of changes, but should be
much faster than the old way which exponentially slowed down to a crawl.
Also fix some popup bugs (leave/forget).
Not working yet: side pane keyboard controls, proper highlight,
room & member filtering, local echo replacement
