Improve server memory usage

We temporarily let it grow when the message size exceed the limit,
but restore the buffer's capacity shortly after. This ensures that,
for each connection in its entire lifetime, we only ever use 1MB.

Introduce context menu to project panel

This can race anyway with snapshot updates, so we just eagerly refresh
the root entry and wait for updates to come in to populate it.

Remove opentelemetry tracing subscriber

We'll see if this stops the server from leaking memory. We still
have spans in our logs.

Co-Authored-By: Antonio Scandurra <me@as-cii.com>

Integration test cleanup

* Use 'build_local_project' helper to reduce boilerplate
* Peform the setup steps in a consistent order

Add a few more important menu items

These will fire whenever the left/right mouse button is pressed down outside a specific region. I'll use these to cancel the context menu in the next commit.

Vim visual line mode

Add a Window application menu

Previously, two right clicks would cause an issue with cancelling the context menu via escape.

Panes now emit an event when adding the first item, so we need to flush
effects between splitting and following in order to avoid accidentally
cancelling the follow.

* Refactor the way the project's active entry is assigned. Assign it
  together with the window title, as opposed to on every notification
  from a pane.
* Emit the ActiveItem event from panes consistently, even when adding
  the first item to an empty pane.

This controls how the window appears in the Window menu.

We won't hover regions from stacking contexts that are below the one being hovered.

Previously, we were using an `EventHandler` which doesn't take into
account other mouse regions floating above the rendered element. This
was problematic because, when clicking the `x` icon on a tab that was
not active, we were first activating it and then closing it.