refactor(tv): Redesign full-screen IPTV player HUD, add loading indicator, and fix catchup seeking

[Himanth-reddy]

Summary

This PR redesigns and refines the Android TV IPTV full-screen playback HUD to provide a premium full-width media layout, exact control centering, scrubber thumb indicator, and UI feedback improvements.

Key Changes

• Full-Width Modern Layout: Updated FullscreenHud.kt to span the full screen width with top category & formatted date/time header and bottom metadata control sheet.
• Centered Playback Controls: Used Box(modifier = Modifier.fillMaxWidth()) with Alignment.Center for exact horizontal alignment of playback buttons (|< , <<, Play/Pause, >>, >|). Positioned elapsed show time on the left and action buttons (Replay, LIVE, GUIDE) on the right.
• Scrubber Thumb Ball: Added a prominent white circular scrubber ball on HudSeekBar when focused (isFocused == true).
• Instant Play/Pause UI Toggle: Implemented local state tracking (localIsPlaying) for 0ms visual button toggle feedback.
• Current Show Elapsed Time: Updated left timer calculation to display total elapsed show duration (clockMillis - now.startUtcMillis).
• Loading Indicator: Centered a CircularProgressIndicator spinner on the player when streams are preparing or buffering (isBuffering == true).
• Git Ignore: Added .agents/ to .gitignore to keep agent customization skills untracked.

[Himanth-reddy]

Known Catchup Issues & Help Requested

While testing the Android TV IPTV player HUD, we encountered two catchup playback bugs where maintainer feedback or community guidance would be greatly appreciated:

1. Catchup Seek Bar Leaping / Violent Seeking:

   • On Xtream Codes / Timeshift IPTV streams, seeking backward or forward across 1-minute segment boundaries occasionally causes position leaps or stream decoding retries (triggering the "Seeking catch-up" popup).

2. Transitioning from Catchup to Live / Other Channels:

   • Returning to Live broadcast from Catchup mode (via the LIVE button) or selecting another channel while playing a catchup program occasionally freezes remote DPAD focus navigation or stalls stream reloading.

screencast-Genymotion-2026-08-07_22.29.08.127.webm

Any feedback, suggestions, or PR contributions from maintainers on resolving these catchup stream behaviors would be very helpful!