Tap the 16:9 thumbnail box on VideoDetail and the video plays right
there in the card — like YouTube. Uses its own ExoPlayer (released on
nav-back via DisposableEffect) with PlayerView's built-in controls
(play/pause/seek/duration bar).
Top-right ⛶ pill on the inline player jumps to the existing fullscreen
PlayerScreen which still has the full toolset (speed picker, audio-only,
share, PiP, background, SponsorBlock chip). Restarts from 0 on entry —
seek-position handoff between inline + fullscreen is a future refinement.
Inline player state (playing/not-playing) is keyed on streamUrl so
navigating to a different video resets it back to the thumbnail-with-
play-overlay default.