Add subtitle swipe controls and playback fixes

[1Selxo]

Summary

• add configurable subtitle swipe controls modeled after asbplayer mobile navigation
• swipe right/left to seek to the next/previous subtitle and swipe up/down to hide/show subtitles
• prevent subtitle swipes from conflicting with horizontal seek and volume/brightness gestures
• remove parenthesized speaker names when they follow ASCII or Unicode dialogue dashes
• use the resumable HTTP downloader for direct video files while retaining FFmpeg for HLS and complex inputs
• show the actionable tail of FFmpeg failures instead of its build banner

Testing

• :app:testDebugUnitTest --tests eu.kanade.tachiyomi.ui.player.utils.SubtitleRegexFiltersTest
• :app:testDebugUnitTest --tests eu.kanade.tachiyomi.data.animedownload.AnimeDownloaderTest
• 8 targeted tests passed
• :app:assembleDebug completed successfully
• installed and launched the arm64 debug APK on a physical Android device