fix(build): disable LTO temporarily and enable PGO based on release settings

refactor(ui): remove unnecessary DOMContentLoaded listener from toolbar registration
fix(ui): trigger window resize event on closing watermark to recalculate layout
refactor(ui): improve animation structure for tab content in vertical tabs manager

src/browser/base/content/ZenStartup.mjs

@@ -58,6 +58,7 @@
 
     closeWatermark() {
       document.documentElement.removeAttribute('zen-before-loaded');
+      window.dispatchEvent(new window.Event('resize')); // To recalculate the layout
       if (Services.prefs.getBoolPref('zen.watermark.enabled', false)) {
         gZenUIManager.motion
           .animate(