Add NavOverflow component and use it in the preview navbar (#3240)

Co-authored-by: codecalm <codecalm@gmail.com>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: codecalm <1282324+codecalm@users.noreply.github.com>

.changeset/nav-overflow.md

@@ -0,0 +1,7 @@
+---
+"@tabler/core": minor
+"@tabler/preview": minor
+"@tabler/docs": minor
+---
+
+Added `NavOverflow` component that moves nav items that do not fit into a More dropdown, with a `.nav-overflow` wrapper.

.changeset/navbar-nav-overflow.md

@@ -0,0 +1,5 @@
+---
+"@tabler/preview": minor
+---
+
+Updated the preview navbar to move menu items that do not fit into a More dropdown with `.nav-overflow`.