Add auto-panning when pointer goes beyond viewport edge with Select tool (#1625)

* Add code to shift viewport if mouse is beyond edge

* Allow shifting viewport if mouse is stationary too

* Group all modifier keys into SelectToolPointerKeys

* Cleanup message ordering to remove shifting during resize

* Slow down shifting by half

* Clamp speed; code review cleanup

---------

Co-authored-by: 0hypercube <0hypercube@gmail.com>
Co-authored-by: Keavon Chambers <keavon@keavon.com>

frontend/wasm/src/editor_api.rs

@@ -239,6 +239,12 @@ impl JsEditorHandle {
 			*g.borrow_mut() = Some(Closure::new(move || {
 				wasm_bindgen_futures::spawn_local(poll_node_graph_evaluation());
 
+				call_closure_with_editor_and_handle(|editor, handle| {
+					for message in editor.handle_message(BroadcastMessage::TriggerEvent(BroadcastEvent::AnimationFrame)) {
+						handle.send_frontend_message_to_js(message);
+					}
+				});
+
 				// Schedule ourself for another requestAnimationFrame callback
 				request_animation_frame(f.borrow().as_ref().unwrap());
 			}));