fix: remove scene thumbnail URL from VLM search results

- Scene thumbnails often don't exist for unprocessed files
- Use regular thumbnail fallback instead of scene-specific URLs
- Eliminates 404 errors in browser console for scene_*.jpg requests

src/views/SearchView.vue

@@ -1147,7 +1147,7 @@ async function sendMessage() {
           summary: vlmDesc ? `[SCENE] ${vlmDesc}` : `Scene ${sceneIndex}`,
           text_content: textContent,
           similarity: s.score ?? null,
-          thumbnail_url: `${base}/api/v1/file/${s.file_uuid}/scenes/scene_${String(sceneIndex).padStart(3, '0')}.jpg`,
+          // Don't set scene thumbnail URL - use regular thumbnail fallback instead
           bilingual,
           vlm_description_en: s.vlm_description,
           vlm_description_localized: s.vlm_description_localized