[duplicated subtitle] Move SubtitleDeduplicator from NewPipeExtractor to app side. [Bug] Fix duplicated subtitle issue.

- Add core deduplicated logic/method
- Reproduce bug with the YouTube video: https://www.youtube.com/watch?v=b7vmW_5HSpE
  (Observed around 2026-03-03: the subtitle language that previously had duplication issue no longer appears in the captions list)
- Introduce `SubtitleDeduplicator.java` to check and remove duplicates, storing results in cache.
- Add `SubtitleOrigin` and `SubtitleState` enums to model subtitle type and state.
- Ensure cache directory is recreated if missing.

Author: TransZAllen