修复下载进度的错误问题

public/js/main.js

@@ -899,6 +899,15 @@ document.addEventListener('DOMContentLoaded', () => {
         }
         resetPhases();
 
+        // Reset subtitle selector before subscribing to ensure we use the base key for source download
+        if (subtitleSelector) {
+            subtitleSelector.innerHTML = '<option value="-1">无字幕</option>';
+            subtitleSelector.value = "-1";
+        }
+        if (subtitlePanel) {
+            subtitlePanel.classList.add('hidden');
+        }
+
         selectedKey = key;
         currentVideoKey = key;
         subscribeToKey(key);
@@ -906,6 +915,12 @@ document.addEventListener('DOMContentLoaded', () => {
         nowPlaying.classList.remove('hidden');
         currentVideoTitle.textContent = key.split('/').pop();
 
+        // If download is needed, show the overlay so the user sees the progress
+        if (!hasDownloadCache) {
+            transcodingOverlay.classList.remove('hidden');
+            showDownloadPhase();
+        }
+
         // Fetch subtitle metadata
         fetchVideoMetadata(selectedBucket, key);
     };