fix: prevent double scrollbar by locking html/body overflow

Added overflow: hidden to html and body, height: 100% to html/body/#root.
Only the <main> element inside AppLayout scrolls. This prevents the
browser's default body scroll from creating a second scrollbar alongside
the app's own scroll container.

apps/web/src/styles/globals.css

@@ -1,5 +1,15 @@
 @import "tailwindcss";
 
+html,
+body {
+  height: 100%;
+  overflow: hidden;
+}
+
+#root {
+  height: 100%;
+}
+
 :root {
   font-family:
     "Inter", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,