Add ability to download srt and txt

Add ability to download srt and txt, screenshots: <img width="1249" height="979" alt="image" src="https://github.com/user-attachments/assets/162ed083-4ef4-4e0a-abd1-26d856450cb3" /> <img width="632" height="387" alt="image" src="https://github.com/user-attachments/assets/684636bf-39e7-4ee2-9d90-89c7ea6f153a" /> Sample files: [result_20251212_233406.txt](https://github.com/user-attachments/files/24139078/result_20251212_233406.txt) [result_20251212_233406.srt.txt](https://github.com/user-attachments/files/24139082/result_20251212_233406.srt.txt) (the `.txt` is manually added since GitHub doesn't allow `.srt` file)