fix(ui): keep closed tooltips hidden before hydration

Tooltip content was hidden only by data-show, which the client applies
after hydration, so server HTML showed every tooltip for a moment on page
load. A closed tooltip ([data-open="false"]) is now hidden in CSS too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ui/components/tooltip.wrn

@@ -189,6 +189,12 @@ id: string = ""
       pointer-events: none;
     }
 
+    /* Closed until hovered or focused, including in server HTML before the
+       client applies data-show; otherwise every tooltip flashes on load. */
+    .wrn-tooltip[data-open="false"] .wrn-tooltip__content {
+      display: none;
+    }
+
     .wrn-tooltip[data-interactive="true"] .wrn-tooltip__content {
       pointer-events: auto;
     }