App: add display canvas

app-proto/sketch-outline/src/display.rs

@@ -0,0 +1,10 @@
+use sycamore::prelude::*;
+
+#[component]
+pub fn Display() -> View {
+    view! {
+        /* [TO DO] switch back to integer-valued parameters when that becomes
+        possible again */
+        canvas(width="750", height="750", tabindex="0")
+    }
+}