Improve query intent handling and preview playback

frontend/app.js

@@ -270,6 +270,33 @@ function attachVideoSource(video, src) {
   logEvent("preview:attach:file", { src });
 }
 
+function startHoverPreview(video, src) {
+  if (!src) {
+    return;
+  }
+  attachVideoSource(video, src);
+  video.classList.remove("hidden");
+  const attemptPlay = () => {
+    video.play().catch((error) => {
+      logEvent("preview:hover:play:error", { src, message: String(error) });
+    });
+  };
+  if (video.readyState >= 2) {
+    attemptPlay();
+    return;
+  }
+  const onReady = () => {
+    video.removeEventListener("loadeddata", onReady);
+    video.removeEventListener("canplay", onReady);
+    attemptPlay();
+  };
+  video.addEventListener("loadeddata", onReady, { once: true });
+  video.addEventListener("canplay", onReady, { once: true });
+  if (video.load) {
+    video.load();
+  }
+}
+
 function detachVideoSource(video) {
   const existing = hlsInstances.get(video);
   if (existing) {
@@ -299,21 +326,20 @@ function renderResults(results) {
     node.querySelector(".result-snippet").textContent = item.snippet || item.reason || item.source || "";
     node.querySelector(".result-reason").textContent = item.reason ? `AI note: ${item.reason}` : "";
     node.querySelector(".source-badge").textContent = item.source;
+    previewVideo.poster = item.thumbnailUrl || "";
     if (item.previewVideoUrl) {
-      attachVideoSource(previewVideo, item.previewVideoUrl);
-      previewVideo.poster = item.thumbnailUrl || "";
       const mediaArea = node.querySelector(".relative");
       mediaArea.addEventListener("mouseenter", () => {
         logEvent("preview:hover:start", { title: item.title, source: item.source, previewVideoUrl: item.previewVideoUrl });
         overlays.forEach((overlay) => overlay.classList.add("hidden"));
-        previewVideo.classList.remove("hidden");
-        previewVideo.play().catch(() => {});
+        startHoverPreview(previewVideo, item.previewVideoUrl);
       });
       mediaArea.addEventListener("mouseleave", () => {
         logEvent("preview:hover:end", { title: item.title, source: item.source });
         previewVideo.pause();
         previewVideo.currentTime = 0;
         previewVideo.classList.add("hidden");
+        detachVideoSource(previewVideo);
         overlays.forEach((overlay) => overlay.classList.remove("hidden"));
       });
     }