feat: portfolio/about listings start locked on their first file

same end state as clicking the first row by hand — hovering other rows no longer steals the preview until you actually click one. clicking a different row still jumps straight to it and relocks there; clicking the locked row again releases it back to hover-browsing. games are excluded (nothing to browse), matched via the game-embed class rather than page context so it stays correct no matter which page a game was launched from.

assets/js/filebrowser.js

@@ -85,6 +85,9 @@
 
     var start = rows.findIndex(function (a) { return a.classList.contains("is-selected"); });
     select(start < 0 ? 0 : start, true);   // initial selection: don't echo into the shell yet
+    // portfolio/about listings start pre-locked on their first file, same as a
+    // manual click — games stay hover-driven, there's nothing else to browse there
+    if (container && !container.classList.contains("game-embed")) setFrozen(true);
 
     // warm the cache so switching between gallery images is instant
     var srcs = rows.map(function (a) { return a.getAttribute("data-img"); }).filter(Boolean);