fix: preserve lazy navigation intent

CHANGELOG.md

@@ -8,6 +8,8 @@ Follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) · versioned wi
 ## [Unreleased]
 
 ### Changed
+- **Lazy-navigation race protection.** A restored-section callback can no longer replace a newer user navigation
+  request while section-specific modules are still loading, including under CPU throttling.
 - **Constrained workload coverage.** Added a 4× CPU-throttled 500-character browser workload regression that
   records bounded DOM/audio/heap/image-cache metrics while preserving pagination.
 - **Bounded library image lifecycle.** Profile, concept-art, and voice-library images now use a viewport-aware

VERSION

@@ -1 +1 @@
-1.24.19
+1.24.20

static/nav.js

@@ -437,7 +437,14 @@
   window._enginesSidebarCat  = localStorage.getItem('ttsvc_engines_cat')  || 'llm';
   var _startSection = window._navRequestedSection || hashSection() || ((_savedSection && SECTIONS.includes(_savedSection)) ? _savedSection : 's-voices');
   if (typeof window.ensureFeatureModules === 'function') {
-    window.ensureFeatureModules(_startSection).then(function () { showSection(_startSection); }, function () { showSection(_startSection); });
+    var activateStart = function () {
+      // A first user click can arrive while the restored section's lazy group
+      // is still loading. Do not let that delayed startup callback overwrite
+      // the newer navigation intent (especially visible under CPU throttling).
+      if (window._navRequestedSection && window._navRequestedSection !== _startSection) return;
+      showSection(_startSection);
+    };
+    window.ensureFeatureModules(_startSection).then(activateStart, activateStart);
   } else showSection(_startSection);
 
   window.addEventListener('hashchange', function () {