fix: restore translucent dashboard styling (#6664)

* fix: restore translucent dashboard styling

* fix: restore dashboard widget transparency

* fix: address dashboard review feedback

* fix: apply board opacity to containers

* fix: flatten demo board container

* fix: default board roundness to sm

* fix: restore assistant widget transparency

* Revert "fix: default board roundness to sm"

This reverts commit c235cbdf2b.

* fix: address remaining dashboard review comments

* test: align grid geometry expectations

packages/widgets/src/notifications/component.module.css

@@ -0,0 +1,10 @@
+.card,
+.row {
+  background-color: transparent;
+  border-color: rgb(from var(--mantine-color-default-border) r g b / calc(var(--opacity, 1) * 0.38));
+}
+
+.row {
+  border-bottom-style: solid;
+  border-bottom-width: 1px;
+}