Fixed: anilist info sometimes missing from search results
This was caused by rate limit on anilist API server. Now trace.moe API would prefetch all anilist info and serve it from cache, so search results (both Web and Telegram bot) would be faster and more reliable.
Improvements: faster video preview generation
Scene boundaries of all video are now pre-analysed before generating video preview, saving about 0.5s-1s scene detection time. This also improves search speed and lowers error rate due to reduced server load. Scene detection method has changed so the cut may not be exactly the same, but should be just as natural as before.