Add Support for Uploading Audio Files to Generate Quizzes

#### Currently, the platform allows quiz generation from text input and document URLs, but it does not support uploading audio files (e.g., .mp3, .wav). Many users consume learning content through recorded lectures, podcasts, and voice notes, so adding audio support would significantly enhance accessibility and usability.

#### By enabling audio uploads, users can directly generate quizzes from spoken content without needing to manually transcribe or convert files beforehand.